Which 1997's accompanying 1991 was a when the tournament was the australian open?
CREATE TABLE table_name_57 (tournament VARCHAR)
SELECT 1997 FROM table_name_57 WHERE 1991 = "a" AND tournament = "australian open"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_name_57 (tournament VARCHAR) Question: Which 1997's accompanying 1991 was a when the tournament was the australian open? [/INST] SELECT 1997 FROM table_name_57 WHERE 1991 = "a" AND tournament = "australian open" </s>