SQL> WITH DATA AS(
  2  SELECT 'vs' str FROM dual UNION ALL
  3  SELECT 'LS' FROM dual UNION ALL
  4  SELECT 'RS' FROM dual UNION ALL
  5  SELECT 'AS' FROM dual)
  6  SELECT ''''||listagg(str,''',''') WITHIN GROUP(ORDER BY rn)||'''' str FROM
  7  (SELECT ROWNUM rn, str FROM DATA);
STR
--------------------------------------------------------------------------------
'vs','LS','RS','AS'

SELECT ''''||listagg(str,''',''') WITHIN GROUP(ORDER BY rn)||'''' str 
FROM
    (SELECT ROWNUM rn, str FROM <your_table_name>);

SQL> declare
  2    a varchar2(200) :='vs';
  3    b varchar2(200);
  4  begin
  5    SELECT name into b FROM vk_domain WHERE name = a and rownum = 1;
  6    dbms_output.put_line('yes');
  7  exception
  8    when no_data_found then dbms_output.put_line('no');
  9  end;
 10  /
yes

PL/SQL procedure successfully completed.