WITH RECURSIVE

WITH RECURSIVE children AS
  ( SELECT '0'::varchar AS parent_code,
           A.level_code,
           A.level_name,
           A.code_length,
           1 AS DEPTH
   FROM c_levels A
   WHERE A.level_code ='05'
   UNION ALL SELECT B.parent_code AS parent_code,
                    B.level_code,
                    B.level_name,
                    B.code_length,
                    DEPTH + 1
   FROM c_levels B
   JOIN children C ON ( B.level_code = C.parent_code ))
SELECT *
FROM children
ORDER BY DEPTH DESC