CREATE TABLE table_204_481 (id DECIMAL, "poll source" TEXT, "date ( s ) \ administered" TEXT, "sample\ size" DECIMAL, "margin of\ error" TEXT, "andrew\ cuomo  ( d ) " TEXT, "rob\ astorino  ( r ) " TEXT, "other" TEXT, "undecided" TEXT)

what poll source had the largest sample size ?
SELECT "poll source" FROM table_204_481 ORDER BY "sample\nsize" DESC LIMIT 1
SELECT "poll source" FROM "table_204_481" ORDER BY "sample\nsize" DESC NULLS LAST LIMIT 1