CREATE TABLE "great_northern_section" (
  "number" text,
  "previous_number_s" real,
  "previous_class" text,
  "converted" real,
  "withdrawn" real,
  "disposal" text
);

Question: With a number of 30, what would be listed for previous number(s)?
SQL: SELECT "previous_number_s" FROM "great_northern_section" WHERE "number"='30';

Question: With a previous number of 68165, what is the oldest converted date?
SQL: SELECT MAX("converted") FROM "great_northern_section" WHERE "previous_number_s"=68165;

Question: With a converted less than 1966 and a number of 32 (2nd), what is the largest number listed for withdrawn?
SQL: SELECT MAX("withdrawn") FROM "great_northern_section" WHERE "number"='32 (2nd)' AND "converted"<1966;