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_31304 ( "Season" text, "Ave. Attendance" real, "+/- ave. on prev. season" text, "Competition" text, "Occupier" text )

### Question ###
What is every value for average on previous season if the competition is league two?

### Accurate SQL ###

SELECT "+/- ave. on prev. season" FROM table_31304 WHERE "Competition" = 'League Two'