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  "withdrawn" real,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

Question: What is the smallest converted value at number 19?
SQL: SELECT MIN("converted") FROM "great_northern_section" WHERE "number"='19';

Question: What is every previous class when the previous number is 61323?
SQL: SELECT "previous_class" FROM "great_northern_section" WHERE "previous_number_s"=61323;

Question: What is every use for number 1?
SQL: SELECT "use" FROM "great_northern_section" WHERE "number"='1';