Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE Staff ( last_name VARCHAR )
TABLE: CREATE TABLE Customers ( last_name VARCHAR )

### Question ###
Which last names are both used by customers and by staff?

### Accurate SQL ###

SELECT last_name FROM Customers INTERSECT SELECT last_name FROM Staff