CREATE TABLE table_20640 ("Danish name" TEXT, "English name" TEXT, "Seat of administration" TEXT, "Largest city" TEXT, "Population  ( January 1 ,  2008 ) " FLOAT, "Area  ( km\\u00b2 ) " FLOAT, "Pop. density  ( per km\\u00b2 ) " TEXT)

In the region where Roskilde is the largest city, what is the seat of administration?
SELECT "Seat of administration" FROM table_20640 WHERE "Largest city" = 'Roskilde'
SELECT "Seat of administration" FROM "table_20640" WHERE "Largest city" = 'Roskilde'