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_81 ( turnout VARCHAR, candidates VARCHAR, valid_poll VARCHAR )

### Question ###
What is the turnout with 15 candidates and more than 377,591 valid poll?

### Accurate SQL ###

SELECT turnout FROM table_name_81 WHERE candidates = 15 AND valid_poll > 377 OFFSET 591