SELECT MIN("Crowd") FROM table_11567 WHERE "Home team" = 'north melbourne'
What is the lowest crowd when North Melbourne played at home?
CREATE TABLE table_11567 (
    "Home team" text,
    "Home team score" text,
    "Away team" text,
    "Away team score" text,
    "Venue" text,
    "Crowd" real,
    "Date" text
)