CREATE TABLE table_37863 ("Local Government Area" TEXT, "Principal town" TEXT, "Land Area  ( km\\u00b2 ) " FLOAT, "Population 2011 census" FLOAT, "Density" FLOAT)

What is the lowest density of a town with a 13,708 2011 population census ?
SELECT MIN("Density") FROM table_37863 WHERE "Population 2011 census" = '13,708'
SELECT MIN("Density") FROM "table_37863" WHERE "Population 2011 census" = '13,708'