The time part of your datetime defaults to 00:00:00 A.M.
HH24:MI:SS, where:
HH24 is a two-digit hour in 24-hour format from 00 to 23.
MI is a two-digit minute from 00 to 59.
SS is a two-digit second from 00 to 59.
SQL> Select TO_DATE('05-FEB-1968 19:32:36', 'DD-MON-YYYY HH24:MI:SS') from dual;
TO_DATE('
---------
05-FEB-68