SELECT LEVEL, MAX('col_name') FROM my_table
WHERE LEVEL = '&n'
CONNECT BY PRIOR ('col_name') > 'col_name')
GROUP BY LEVEL;
 
-- Example :
--
-- Given a table called emp with the following columns:
--   id   number
--   name varchar2(20)
--   sal  number
--
-- For the second highest salary:
 
SELECT LEVEL, MAX(sal) FROM emp
WHERE LEVEL=2
CONNECT BY PRIOR sal > sal
GROUP BY LEVEL