select to_char(sysdate, 'Month') from dual
no seu exemplo será:
select to_char(to_date('15-11-2010', 'DD-MM-YYYY'), 'Month') from dual
select to_char(sysdate, 'Month') from dual
select to_char(to_date('15-11-2010', 'DD-MM-YYYY'), 'Month') from dual