Oracle doesn’t support limit

My god sometime I bang my head on the wall to do something simple on oracle. So oracle don’t support limit so to do something simple has :

SELECT f_name, l_name, age from
employee_data ORDER BY age DESC
LIMIT 20

become :

SELECT f_name, l_name, age
FROM
( SELECT f_name, l_name, age, ROWNUM r
FROM
( SELECT f_name, l_name, age FROM employee_data 
      ORDER BY age DESC
)
WHERE ROWNUM <= 40
)
WHERE r >= 21;