create or replace
function consulta_cedula
(id_cedula in number) return varchar2 is
---
v_cedula number(5);

begin
select count(*)
into v_cedula
from padron_ciudadanos
where id_cedula = v_cedula;
--
if v_cedula = id_cedula then
return 'S';
else
return 'N';
end if;
end;

---------

--Para leer la funcion y me devuelva por consola

SET SERVEROUTPUT ON

declare
valor varchar2(1) := consulta_cedula(1);
begin
dbms_output.put_line('valor');
end;