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 Customers (date_became_customer VARCHAR, first_name VARCHAR, last_name VARCHAR)

### Question ###
When did customer with first name as Carole and last name as Bernhard became a customer?

### Accurate SQL ###

SELECT date_became_customer FROM Customers WHERE first_name = "Carole" AND last_name = "Bernhard"