WHich Surface has an Opponent of gustavo kuerten?
CREATE TABLE table_name_13 (surface VARCHAR, opponent VARCHAR)
SELECT surface FROM table_name_13 WHERE opponent = "gustavo kuerten"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_name_13 (surface VARCHAR, opponent VARCHAR) Question: WHich Surface has an Opponent of gustavo kuerten? [/INST] SELECT surface FROM table_name_13 WHERE opponent = "gustavo kuerten" </s>