Which line has an operator of the London Overground and ends at the Crystal Palace?
CREATE TABLE "services" (
  "platform" real,
  "frequency_per_hour" real,
  "destination" text,
  "service_pattern" text,
  "operator" text,
  "line" text
);
SELECT "line" FROM "services" WHERE "operator"='london overground' AND "destination"='crystal palace';