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_20 ( highest INTEGER, average VARCHAR, capacity VARCHAR )

### Question ###
What's the highest with a capacity of greater than 4,000 and an average of 615?

### Accurate SQL ###

SELECT MAX(highest) FROM table_name_20 WHERE average = 615 AND capacity > 4 OFFSET 000