CREATE TABLE table_204_558 (id DECIMAL, "name" TEXT, "location" TEXT, "city" TEXT, "listing date" TEXT)

which city is home to the greatest number of historic sites , existing or demolished ?
SELECT "city" FROM table_204_558 GROUP BY "city" ORDER BY COUNT(*) DESC LIMIT 1
SELECT "city" FROM "table_204_558" GROUP BY "city" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1