CREATE TABLE Customers (date_became_customer VARCHAR2, first_name VARCHAR2, last_name VARCHAR2)

When did customer with first name as Carole and last name as Bernhard became a customer?
SELECT date_became_customer FROM Customers WHERE first_name = "Carole" AND last_name = "Bernhard"
SELECT "date_became_customer" FROM "Customers" WHERE "Bernhard" = "last_name" AND "Carole" = "first_name"