Creating Oracle Database Table with Numeric Permission Level

Question

I am creating an Oracle database with a table called Roles.
I want the Permission_Level row to store values 1,2,3,4, or 5. How to I limit the input to only those numbers? Here is my attempt:

    CREATE TABLE ROLES 
(
  ROLE_ID NUMBER(20) NOT NULL 
, ROLE_NAME VARCHAR2(20) NOT NULL 
, PERMISSION_LEVEL NUMBER(1,0) NOT NULL 
, CONSTRAINT ROLES_PK PRIMARY KEY 
  (
    ROLE_ID 
  )
  ENABLE 
);