CREATE TABLE table_53883 ("Episode" TEXT, "Air Date" TEXT, "Timeslot" TEXT, "Rating" FLOAT, "Share" FLOAT, "18-49  ( Rating/Share ) " TEXT, "Viewers  ( m ) " FLOAT, "Rank  ( Timeslot ) " FLOAT, "Rank  ( Night ) " TEXT, "Rank  ( Overall ) " FLOAT)

How many viewers have an Air Date of march 20, 2008, and an 18-49 (Rating/Share) of 2.3/7?
SELECT "Viewers (m)" FROM table_53883 WHERE "Air Date" = 'march 20, 2008' AND "18-49 (Rating/Share)" = '2.3/7'
SELECT "Viewers (m)" FROM "table_53883" WHERE "18-49 (Rating/Share)" = '2.3/7' AND "Air Date" = 'march 20, 2008'