CREATE TABLE table_57506 ("Home team" TEXT, "Home team score" TEXT, "Away team" TEXT, "Away team score" TEXT, "Venue" TEXT, "Crowd" FLOAT, "Date" TEXT)

What was the largest crowd when South Melbourne was the away team?
SELECT MAX("Crowd") FROM table_57506 WHERE "Away team" = 'south melbourne'
SELECT MAX("Crowd") FROM "table_57506" WHERE "Away team" = 'south melbourne'