PLSqlの戻り値

SQLだけを使用してみませんか：

   SELECT MAX(ltrim(sys_connect_by_path(flow_run_id, ','), ','))
   FROM
   (
    select flow_run_id, rownum rn
    from table
    where CREATED_DATE < sysdate - 32
    and rownum < 10
    order by 1 desc
   )
   START WITH rn = 1
   CONNECT BY PRIOR rn = rn - 1