CREATE TABLE table_12637 ("Clubs" TEXT, "Seasons at this level" TEXT, "Settlements" TEXT, "Season joined league" TEXT, "Position in 1960/1961" TEXT)

Which club has played for 27 seasons at this level?
SELECT "Clubs" FROM table_12637 WHERE "Seasons at this level" = '27 seasons'
SELECT "Clubs" FROM "table_12637" WHERE "Seasons at this level" = '27 seasons'