eSQL Case is throwing ORA-01427

Hi

I have a query which is throwing ORA-01427 at CASE. I am looking for a fix or alternate for this.

eg.,

SQL> select ename,case deptno when 20 then ( select dname from scott.dept where deptno=deptno )

when 10 then ( select distinct dname from scott.dept where deptno=deptno ) end from scott.emp;

select ename,case deptno when 20 then ( select dname from scott.dept where deptno=deptno )

*

ERROR at line 1:

ORA-01427: single-row subquery returns more than one row