Question: In what year did Leroy Sievers begin serving as the executive producer "Nightline"?
Sentence (from "Leroy Sievers"): Leroy Sievers (June 16, 1955 – August 15, 2008) was a journalist who won 12 national news Emmy Awards, two Peabody Awards, and two Alfred I. duPont-Columbia University Awards.
Relevant evidence: No