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_30 (surface VARCHAR, outcome VARCHAR, score VARCHAR)
### Question:
On what Surface was the match with a Score of 6–4, 6–3 and Runner-up Outcome played?
### Answer:
SELECT surface FROM table_name_30 WHERE outcome = "runner-up" AND score = "6–4, 6–3"