sql_text not appearing in v$sql

I ran the following query to figure out why the sessions were hanging .

col event format a30

col sample_time format a25

select session_id, sample_time, session_state, event, wait_time, time_waited, sql_id, sql_child_number CH#

from v$active_session_history

where user_id = 104

and sample_time between

    to_date('15-JUNE-16 06.55.00 PM','dd-MON-yy hh:mi:ss PM')

       and

    to_date('15-JUNE-16 07.10.00 PM','dd-MON-yy hh:mi:ss PM')

order by session_id, sample_time;

I got the following output from the above query .

61 15-JUN-16 07.09.08.367 PM WAITING enq: TX - row lock contention           0           0 fx60htyzmz6wv          0