CREATE TABLE table_27651 ("Letters" TEXT, "Organization" TEXT, "Nickname" TEXT, "Founding Date" TEXT, "Founding University" TEXT, "Type" TEXT)

If the founding university is in Washington, D.C., what was the founding date?
SELECT "Founding Date" FROM table_27651 WHERE "Founding University" = 'Washington, D.C.'
SELECT "Founding Date" FROM "table_27651" WHERE "Founding University" = 'Washington, D.C.'