CREATE TABLE "br_railbuses" (
  "number_range" text,
  "builder" text,
  "introduced" real,
  "no_built" real,
  "region" text,
  "withdrawn" real
);

Question: What is the minimum introduced value for the Departmental region?
SQL: SELECT MIN("introduced") FROM "br_railbuses" WHERE "region"='Departmental';

Question: What is the smallest introduced value?
SQL: SELECT MIN("introduced") FROM "br_railbuses";