CREATE TABLE table_47921 ("Team" TEXT, "Outgoing manager" TEXT, "Manner of departure" TEXT, "Date of vacancy" TEXT, "Replaced by" TEXT, "Date of appointment" TEXT, "Position in table" TEXT)

Who replaced the manager of team arminia bielefeld?
SELECT "Replaced by" FROM table_47921 WHERE "Team" = 'arminia bielefeld'
SELECT "Replaced by" FROM "table_47921" WHERE "Team" = 'arminia bielefeld'