When 42.903° n is the latitude how many measurements of longitude are there?
CREATE TABLE "list_of_foreshocks_and_aftershocks" (
  "date_yyyy_mm_dd" text,
  "time_utc" text,
  "latitude" text,
  "longitude" text,
  "depth" text,
  "magnitude" text
);
SELECT COUNT("longitude") FROM "list_of_foreshocks_and_aftershocks" WHERE "latitude"='42.903° N';