CREATE TABLE table_51839 ("Home team" TEXT, "Home team score" TEXT, "Away team" TEXT, "Away team score" TEXT, "Venue" TEXT, "Crowd" FLOAT, "Date" TEXT)

What was the away team's score when Collingwood was the home team?
SELECT "Away team score" FROM table_51839 WHERE "Home team" = 'collingwood'
SELECT "Away team score" FROM "table_51839" WHERE "Home team" = 'collingwood'