SQL> select (to_date('22-Mar-2007 13:01:42','DD-Mon-YYYY HH24:MI:SS')
  2          -to_date('22-Mar-2007 10:22:12','DD-Mon-YYYY HH24:MI:SS'))*86400 seconds
  3  from dual;
   SECONDS
----------
      9570

1 row selected.

SQL> with 
  2    data as (
  3      select (to_date('22-Mar-2007 13:01:42','DD-Mon-YYYY HH24:MI:SS')
  4              -to_date('22-Mar-2007 10:22:12','DD-Mon-YYYY HH24:MI:SS'))*86400 seconds
  5      from dual
  6    )
  7  select trunc(seconds/3600) hours,
  8         trunc(mod(seconds,3600)/60) minutes,
  9         mod(seconds,60) seconds
 10  from data
 11  /
     HOURS    MINUTES    SECONDS
---------- ---------- ----------
         2         39         30

1 row selected.