What is the elevation of the city with a number of 91,385 Housing dwellings in 2007?
CREATE TABLE "population_by_district" (
  "city_district" text,
  "area_km" text,
  "population_2007_census_hab" text,
  "housing_2007" text,
  "density_hab_km" text,
  "elevation_msl" text
);
SELECT "elevation_msl" FROM "population_by_district" WHERE "housing_2007"='91,385';