Who narrated the lap-by-lap to a 13.4 million audience?
CREATE TABLE "cbs_era_1979_2000" (
  "year" real,
  "network" text,
  "lap_by_lap" text,
  "color_commentator_s" text,
  "pit_reporters" text,
  "host" text,
  "ratings" text,
  "viewers" text
);
SELECT "lap_by_lap" FROM "cbs_era_1979_2000" WHERE "viewers"='13.4 million';