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_15331868_1 ( won INTEGER, points VARCHAR )

### Question ###
What is the highest number won when the number of points is 31?

### Accurate SQL ###

SELECT MAX(won) FROM table_15331868_1 WHERE points = 31