Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE Customers (last_name VARCHAR); CREATE TABLE Staff (last_name VARCHAR)
### Question:
Which last names are both used by customers and by staff?
### Answer:
SELECT last_name FROM Customers INTERSECT SELECT last_name FROM Staff