Oracle 18c

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CREATE TABLE table_name ( created_time ) AS
SELECT TIMESTAMP '2010-01-01 00:10:00' FROM DUAL UNION ALL
SELECT TIMESTAMP '2011-02-01 02:20:00' FROM DUAL UNION ALL
SELECT TIMESTAMP '2012-03-01 04:30:00' FROM DUAL UNION ALL
SELECT TIMESTAMP '2013-04-01 06:40:00' FROM DUAL UNION ALL
SELECT TIMESTAMP '2014-05-01 08:50:00' FROM DUAL UNION ALL
SELECT TIMESTAMP '2015-06-01 10:00:00' FROM DUAL UNION ALL
SELECT TIMESTAMP '2016-07-01 12:10:00' FROM DUAL UNION ALL
SELECT TIMESTAMP '2017-08-01 14:20:00' FROM DUAL UNION ALL
SELECT TIMESTAMP '2018-09-01 16:30:00' FROM DUAL UNION ALL
SELECT TIMESTAMP '2019-10-01 18:40:00' FROM DUAL UNION ALL
SELECT TIMESTAMP '2020-11-01 20:50:00' FROM DUAL UNION ALL
SELECT TIMESTAMP '2021-12-01 22:00:00' FROM DUAL;
12 rows affected

SELECT *
FROM   table_name
WHERE  EXTRACT( MONTH from created_time ) IN ( 11, 12 )


CREATED_TIME


01-NOV-20 20.50.00.000000000

01-DEC-21 22.00.00.000000000


SELECT *
FROM   table_name
WHERE  TO_CHAR( created_time, 'MM' ) IN ( '11', '12' )


CREATED_TIME


01-NOV-20 20.50.00.000000000

01-DEC-21 22.00.00.000000000