CREATE TABLE "class_b_0_6_0" (
  "class" text,
  "wheel_arrangement" text,
  "fleet_number_s" text,
  "manufacturer" text,
  "year_made" text,
  "quantity_made" text,
  "quantity_preserved" text
);

Question: What manufacturer made 6 and preserved 1?
SQL: SELECT "manufacturer" FROM "class_b_0_6_0" WHERE "quantity_made"='6' AND "quantity_preserved"='1';

Question: How many did alco -schenectady preserve of class b-3?
SQL: SELECT "quantity_preserved" FROM "class_b_0_6_0" WHERE "manufacturer"='alco -schenectady' AND "class"='b-3';

Question: What manufacturer made class b-2?
SQL: SELECT "manufacturer" FROM "class_b_0_6_0" WHERE "class"='b-2';