Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_97 (surface VARCHAR, tournament VARCHAR, date VARCHAR)

### Question ###
What type of surface was used for the carthage tournament on august 14, 1994?

### Accurate SQL ###

SELECT surface FROM table_name_97 WHERE tournament = "carthage" AND date = "august 14, 1994"