CREATE TABLE table_58254 ("Home team" TEXT, "Home team score" TEXT, "Away team" TEXT, "Away team score" TEXT, "Venue" TEXT, "Crowd" FLOAT, "Date" TEXT)

What is the crowd size of the match featuring North Melbourne as the away team?
SELECT MIN("Crowd") FROM table_58254 WHERE "Away team" = 'north melbourne'
SELECT MIN("Crowd") FROM "table_58254" WHERE "Away team" = 'north melbourne'