If the vehicle category is multi-axle vehicle, what is the till aligarh?
CREATE TABLE "toll_rates" (
  "vehicle_category" text,
  "till_aligarh" real,
  "till_mathura" real,
  "till_agra" real,
  "for_round_trip" real
);
SELECT MIN("till_aligarh") FROM "toll_rates" WHERE "vehicle_category"='Multi-axle Vehicle';