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_31237 ( "Round" text, "Clubs remaining" real, "Clubs involved" real, "Winners from previous round" real, "New entries this round" text, "Leagues entering at this round" text )

### Question ###
How many different values of clubs involved were there when the league entering at this round was allsvenskan?

### Accurate SQL ###

SELECT COUNT("Clubs involved") FROM table_31237 WHERE "Leagues entering at this round" = 'Allsvenskan'