CREATE TABLE candidate (candidate_id DECIMAL, people_id DECIMAL, poll_source TEXT, date TEXT, support_rate DECIMAL, consider_rate DECIMAL, oppose_rate DECIMAL, unsure_rate DECIMAL)
CREATE TABLE people (people_id DECIMAL, sex TEXT, name TEXT, date_of_birth TEXT, height DECIMAL, weight DECIMAL)

Find the id of the candidate who got the lowest oppose rate.
SELECT candidate_id FROM candidate ORDER BY oppose_rate LIMIT 1
SELECT "candidate_id" FROM "candidate" ORDER BY "oppose_rate" NULLS FIRST LIMIT 1