CREATE TABLE table_64009 ("Serial No." FLOAT, "District" TEXT, "Headquartered City" TEXT, "City Population  ( 2009 ) " FLOAT, "City Area ( km 2  ) " FLOAT)

What was the lowest city population for the district of rajanpur district with a area of 6 km squared and a serial number less than 29?
SELECT MIN("City Population (2009)") FROM table_64009 WHERE "City Area(km 2 )" = '6' AND "District" = 'rajanpur district' AND "Serial No." < '29'
SELECT MIN("City Population (2009)") FROM "table_64009" WHERE "City Area(km 2 )" = '6' AND "District" = 'rajanpur district' AND "Serial No." < '29'