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 (open_cup VARCHAR, reg_season VARCHAR)

### Question ###
What open cup did they play in when they finished 2nd, northeast in the reg. season?

### Accurate SQL ###

SELECT open_cup FROM table_name_21 WHERE reg_season = "2nd, northeast"