What's the length of the route with junctions of ur 1472 sh 255?
CREATE TABLE "farm_to_market_roads" (
  "route_name" text,
  "direction" text,
  "termini" text,
  "junctions" text,
  "length" text,
  "population_area" text
);
SELECT "length" FROM "farm_to_market_roads" WHERE "junctions"='ur 1472 sh 255';