SQL> col level1 format a10
SQL> col level2 format a10
SQL> col level3 format a10
SQL> with
  2    data as (
  3      select sys_connect_by_path(child_t,'/') path,
  4             connect_by_root child_t root, level lvl
  5      from test_1
  6      where level <= 3
  7      connect by prior child_t = parent_t
  8      start with parent_t is null
  9    )
 10  select case lvl
 11           when 1 then substr(path, instr(path,'/',-1,1)+1)
 12           when 2 then substr(path, instr(path,'/',-1,2)+1,
 13                              instr(path,'/',-1,1)-instr(path,'/',-1,2)-1)
 14           else substr(path, instr(path,'/',-1,3)+1,
 15                       instr(path,'/',-1,2)-instr(path,'/',-1,3)-1)
 16         end level1,
 17         case
 18           when lvl in (1,2) then substr(path, instr(path,'/',-1,1)+1)
 19           else substr(path, instr(path,'/',-1,2)+1,
 20                       instr(path,'/',-1,1)-instr(path,'/',-1,2)-1)
 21         end level2,
 22         substr(path, instr(path,'/',-1,1)+1) level3
 23  from data
 24  order by root, lvl
 25  /
LEVEL1     LEVEL2     LEVEL3
---------- ---------- ----------
NEEL       NEEL       NEEL
NEEL       KAMAL      KAMAL
NEEL       KAMAL      KUMAR