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_85 (opponents VARCHAR, surface VARCHAR, date VARCHAR)
### Question:
Who were the opponents that played on a hard surface on July 13, 2008?
### Answer:
SELECT opponents FROM table_name_85 WHERE surface = "hard" AND date = "july 13, 2008"