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_57312 ( "Home team" text, "Home team score" text, "Away team" text, "Away team score" text, "Venue" text, "Crowd" real, "Date" text )

### Question ###
What is the average crowd size for Brunswick street oval?

### Accurate SQL ###

SELECT AVG("Crowd") FROM table_57312 WHERE "Venue" = 'brunswick street oval'