What is the urban sub-area with an East Dunbartonshire council area and a population of 19,020?
CREATE TABLE "references" (
  "rank" text,
  "urban_sub_area" text,
  "population" text,
  "status" text,
  "council_area" text
);
SELECT "urban_sub_area" FROM "references" WHERE "council_area"='east dunbartonshire' AND "population"='19,020';