User LOGON/LOGOFF time

User LOGON/LOGOFF time 

col username for a15
col terminal for a6
col timestamp for a15
col logoff_time for a15
col action_name for a8
col returncode for 9999
select     username,
   terminal,
   action_name,
   to_char(timestamp,'DDMMYYYY:HHMISS') timestamp,
   to_char(logoff_time,'DDMMYYYY:HHMISS') logoff_time,
   returncode
from       dba_audit_session
/