CREATE TABLE table_73721 ("Year" TEXT, "Superintendent" TEXT, "Middlesex Principal" TEXT, "Gorham Principal" TEXT, "Middle School Principal" TEXT, "High School Principal" TEXT)

Who were the middle school principal(s) in 2010-2011?
SELECT "Middle School Principal" FROM table_73721 WHERE "Year" = '2010-2011'
SELECT "Middle School Principal" FROM "table_73721" WHERE "Year" = '2010-2011'