Use um literal de intervalo :
SELECT SYSDATE - INTERVAL '10 00:05' DAY(2) TO MINUTE
FROM DUAL
Ou:
SELECT SYSDATE - INTERVAL '10' DAY - INTERVAL '5' MINUTE
FROM DUAL
Ou apenas use aritmética:
SELECT SYSDATE - 10 /* Days */ - 5 / 24 /60 /* Minutes */
FROM DUAL
Ou use
NUMTODSINTERVAL
:SELECT SYSDATE - NUMTODSINTERVAL( 10, 'DAY' ) - NUMTODSINTERVAL( 5, 'MINUTE' )
FROM DUAL
