select max(salary) from tablename
fetch first 10 rows only

Sorry.. Answer 1 given by me is incorrect.

Correct Query is 

select disntinct salary from tablename
Order by salary
Fetch first 10 rows only

select top 10 salary from table name order by salary;

The query will be like this:

Select distinct salary from table
order by salary desc
fetch first 10 rows only

select distinct  salary from table name hwre rownum <=10