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_15 (date INTEGER, surface VARCHAR, championship VARCHAR)
### Question:
What is the earliest Date on a Surface of clay in a Championship in Linz, Austria?
### Answer:
SELECT MIN(date) FROM table_name_15 WHERE surface = "clay" AND championship = "linz, austria"