What was spent per voter when the spent per vote was 20.07?
CREATE TABLE "campaign_expenses" (
  "candidate_party" text,
  "amount_raised_php" text,
  "amount_spent_php" text,
  "votes" real,
  "spent_per_vote_php" text,
  "spent_per_voter_php" text
);
SELECT "spent_per_voter_php" FROM "campaign_expenses" WHERE "spent_per_vote_php"='20.07';