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 table_name_21 (began INTEGER, court_surface VARCHAR, location VARCHAR)
### Question:
what is the earliest began when the court surface is clay in hamburg?
### Answer:
SELECT MIN(began) FROM table_name_21 WHERE court_surface = "clay" AND location = "hamburg"