CREATE TABLE table_39239 ("Polling Firm" TEXT, "Date" TEXT, "Venstre  ( V ) " TEXT, "Social Democrats  ( A ) " TEXT, "Danish People's Party  ( O ) " TEXT, "Socialist People's Party  ( F ) " TEXT, "Conservative People's Party  ( C ) " TEXT, "Social Liberal Party  ( B ) " TEXT, "Liberal Alliance  ( I ) " TEXT, "Red-Green Alliance  ( \\u00d8 ) " TEXT, "Christian Democrats  ( K ) " TEXT, "Government" TEXT, "Opposition" TEXT)

What opposition do 31.1% of Social Democrats have?
SELECT "Opposition" FROM table_39239 WHERE "Social Democrats (A)" = '31.1%'
SELECT "Opposition" FROM "table_39239" WHERE "Social Democrats (A)" = '31.1%'