What was the maximum vertical measurement if the horizon measurement is 640?
CREATE TABLE "table1_272313_1" (
  "vertical" real,
  "horizontal" real,
  "aspect_ratio" text,
  "pixel_aspect_ratio" text,
  "scanning" text,
  "frame_rate_hz" text
);
SELECT MAX("vertical") FROM "table1_272313_1" WHERE "horizontal"=640;