CREATE TABLE table_54918 ("Home team" TEXT, "Home team score" TEXT, "Away team" TEXT, "Away team score" TEXT, "Venue" TEXT, "Crowd" FLOAT, "Date" TEXT)

What was the biggest crowd when South Melbourne was an away team?
SELECT MAX("Crowd") FROM table_54918 WHERE "Away team" = 'south melbourne'
SELECT MAX("Crowd") FROM "table_54918" WHERE "Away team" = 'south melbourne'