CREATE TABLE table_15977 ("#" FLOAT, "City" TEXT, "1981 Census" FLOAT, "1991 Census" FLOAT, "2001 Census" FLOAT, "2010 Est." FLOAT, "Region" TEXT)

How many 2001 censuses are there on number 13?
SELECT COUNT("2001 Census") FROM table_15977 WHERE "#" = '13'
SELECT COUNT("2001 Census") FROM "table_15977" WHERE "#" = '13'