CREATE TABLE table_203_43 (id DECIMAL, "polling firm" TEXT, "month" TEXT, "link" TEXT, "favor" DECIMAL, "oppose" DECIMAL)

which was the only polling firm to show more than 50 percent in favor of same sex marriage in 2006 ?
SELECT "polling firm" FROM table_203_43 WHERE "favor" > 50 AND "month" = 2006
SELECT "polling firm" FROM "table_203_43" WHERE "favor" > 50 AND "month" = 2006