CREATE TABLE table_51609 ("Home team" TEXT, "Home team score" TEXT, "Away team" TEXT, "Away team score" TEXT, "Venue" TEXT, "Crowd" FLOAT, "Date" TEXT)

When the home team north melbourne was playing what did they score?
SELECT "Home team score" FROM table_51609 WHERE "Home team" = 'north melbourne'
SELECT "Home team score" FROM "table_51609" WHERE "Home team" = 'north melbourne'