CREATE TABLE table_57825 ("Home team" TEXT, "Home team score" TEXT, "Away team" TEXT, "Away team score" TEXT, "Venue" TEXT, "Crowd" FLOAT, "Date" TEXT)

How big was the crowd in game that featured the visiting team of north melbourne?
SELECT "Crowd" FROM table_57825 WHERE "Away team" = 'north melbourne'
SELECT "Crowd" FROM "table_57825" WHERE "Away team" = 'north melbourne'