What SQL is currently using the most resources?

SELECT active_session_history.user_id,
dba_users.username, sqlarea.sql_text,
SUM(active_session_history.wait_time + active_session_history.time_waited) total_wait_time
FROM v$active_session_history active_session_history,
v$sqlarea sqlarea, dba_users
WHERE active_session_history.sample_time BETWEEN SYSDATE - 60/2880 AND SYSDATE
AND active_session_history.sql_id = sqlarea.sql_id
AND active_session_history.user_id = dba_users.user_id
GROUP BY active_session_history.user_id,sqlarea.sql_text, dba_users.username
ORDER BY 4;