`Erro de caractere inválido `ao executar o procedimento oracle usando `getclobval()`

SQL> CREATE OR REPLACE PROCEDURE pivot (v_recordset OUT SYS_REFCURSOR)
  2  AS
  3     --v_recordset SYS_REFCURSOR;
  4     v_sql     LONG;
  5     v_cols_1  LONG;
  6     v_cols_2  CLOB;
  7  BEGIN
  8     SELECT LISTAGG ('''' || "level" || ''' AS "' || "level" || '"', ',')
  9               WITHIN GROUP (ORDER BY "level" DESC)
 10       INTO v_cols_1
 11       FROM (SELECT DISTINCT "level"
 12               FROM tempt);
 13
 14     SELECT DBMS_XMLGEN.CONVERT (
 15               RTRIM (
 16                  XMLAGG (XMLELEMENT (
 17                             e,
 18                                'MAX(CASE WHEN CATEGORY = '
 19                             || CHR (39)
 20                             || CATEGORY
 21                             || CHR (39)
 22                             || ' THEN '
 23                             || CHR (39)
 24                             || "level"
 25                             || CHR (39)
 26                             || ' END) AS '
 27                             || "level"
 28                             || '_'
 29                             || CATEGORY
 30                             || '',
 31                             ',')
 32                          ORDER BY 1 DESC).EXTRACT ('//text()').getclobval (),
 33                  ','))
 34       INTO v_cols_2
 35       FROM (SELECT DISTINCT "level", CATEGORY
 36               FROM tempt);
 37
 38     v_sql := 'SELECT "set", ' || v_cols_2 || '
 39       FROM
 40       (
 41        SELECT *
 42          FROM tempt
 43             PIVOT
 44             (
 45              MAX(value) FOR "level" IN ( ' || v_cols_1 || ' )
 46             )
 47            )
 48            GROUP BY "set"
 49            ORDER BY "set"';
 50     v_sql := REPLACE (v_sql, ''', CHR (39));
 51     DBMS_OUTPUT.PUT_LINE (v_sql);
 52
 53     OPEN v_recordset FOR v_sql;
 54  END pivot;
 55  /

Procedure created.

SQL>

SQL> SET SERVEROUTPUT ON
SQL> DECLARE
  2     l_rc  SYS_REFCURSOR;
  3  BEGIN
  4     pivot (l_rc);
  5  END;
  6  /
SELECT "set", MAX(CASE WHEN CATEGORY = 'GHI' THEN 'Y' END) AS Y_GHI,MAX(CASE
WHEN CATEGORY = 'ABC' THEN 'Y' END) AS Y_ABC,MAX(CASE WHEN CATEGORY = 'ABC' THEN
'Z' END) AS Z_ABC,MAX(CASE WHEN CATEGORY = 'DEF' THEN 'Z' END) AS Z_DEF,MAX(CASE
WHEN CATEGORY = 'IJK' THEN 'X' END) AS X_IJK,MAX(CASE WHEN CATEGORY = 'GHI' THEN
'Z' END) AS Z_GHI,MAX(CASE WHEN CATEGORY = 'DEF' THEN 'X' END) AS X_DEF,MAX(CASE
WHEN CATEGORY = 'ABC' THEN 'X' END) AS X_ABC,MAX(CASE WHEN CATEGORY = 'DEF' THEN
'Y' END) AS Y_DEF
     FROM
     (
      SELECT *
        FROM tempt

PIVOT
           (
            MAX(value) FOR "level" IN ( 'Z' AS "Z",'Y' AS
"Y",'X' AS "X" )
           )
          )
          GROUP BY "set"

ORDER BY "set"

PL/SQL procedure successfully completed.

SQL>

SQL> SELECT "set", MAX(CASE WHEN CATEGORY = 'GHI  <snip>
ORY = 'DEF' THEN 'Z' END) AS Z_DEF,MAX(CASE WHEN  <snip>
(CASE WHEN CATEGORY = 'ABC' THEN 'X' END) AS X_A  <snip>
  2       FROM
  3       (
  4        SELECT *
  5          FROM tempt
  6             PIVOT
  7             (
  8              MAX(value) FOR "level" IN ( 'Z'
  9             )
 10            )
 11            GROUP BY "set"
 12            ORDER BY "set"
 13  /

s Y Y Z Z X Z X X Y
- - - - - - - - - -
A Y Y Z Z   Z X X Y
B   Y Z Z X   X X Y
C   Y Z Z     X X Y
D Y Y Z Z   Z X X Y
E   Y Z Z     X X Y

SQL>