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_21 ( opponent VARCHAR, method VARCHAR, record VARCHAR )

### Question ###
What was the name of the opponent when the method was ko (slam), and record was 13 1?

### Accurate SQL ###

SELECT opponent FROM table_name_21 WHERE method = "ko (slam)" AND record = "13–1"