a nice set based solution. replace the number '7' with whichever N is of interest

select salary from Employees group by salary
having salary =
(select MIN(top_salary.list) from
    (select top 7 distinct_salaries.s as list from
        (select distinct salary as s from Employees
            group by salary) distinct_salaries
    order by distinct_salaries.s desc) top_salary
)

select * from emp

where sal=(select max(sal) from emp

where level=&level connect by prior sal>sal group bu level)

SELECT Salary FROM
(
SELECT ROWNUM AS SN, Salary FROM
(
SELECT DISTINCT Salary FROM Emp ORDER BY Salary DESC
)
)
WHERE SN = N;