Question: Who was appointed the seat left vacant by a former Las Vegas, Nevada politician in the United States Senate Election in Nevada 2012?

Context paragraphs:
United States Senate election in Nevada, 2012: The 2012 United States Senate election in Nevada was held on Tuesday, November 6, 2012, alongside 33 other elections to the United States Senate in other states, as well as elections to the United States House of Representatives, and the 2012 United States presidential election.  The primary election was held June 12, 2012.  Incumbent Republican U.S. Senator Dean Heller, who was recently appointed to this seat left vacant by resigning U.S. Senator John Ensign, was narrowly elected to his first full term over Congresswoman Shelley Berkley.

John Ensign: John Eric Ensign (born March 25, 1958) is an American veterinarian and former politician based in Las Vegas, Nevada.  He was a Congressman and United States Senator from Nevada, serving in the latter seat from January 2001 until May 2011.  He resigned amid a Senate Ethics Committee investigation.

Albert Butler: Albert Butler is an American politician who is currently a Mississippi state senator.  He was sworn into post in March 2010.  Former Claibourne County supervisor Butler, a Democrat, was elected in a special vote to fill a senate seat left vacant when Butler's predecessor, Vincent Davis, was appointed a chancery judge.

Hisako Ōishi: Hisako Ōishi (大石 尚子 , Ōishi Hisako , August 26, 1936 – January 4, 2012) was a Japanese politician of the Democratic Party of Japan, a member of the House of Councillors in the Diet (national legislature).  She was born in Etajima, Hiroshima, grew up in Kamakura, Kanagawa Prefecture and a graduate of Yokohama National University.  She served in the assembly of Kanagawa Prefecture for five terms since 1971 and in the House of Representatives in Diet for two terms since 2000.  In the 2005 general election, she lost her electoral district (Kanagawa 4) to Liberal Democrat Jun Hayashi and also failed to win a proportional seat.  After that, she made an unsuccessful for the House of Councillors in 2007 when she received 59,718 votes nationwide and ranked 21st on the Democratic list while the Democratic Party only won 20 proportional seats, thereby becoming the top replacement for a seat falling vacant.  On December 28, 2007 she took over the seat left vacant by Takashi Yamamoto when he died of cancer.

Alex Sanders (politician): Alexander Mullings "Alex" Sanders, Jr. (born September 29, 1939) is an American politician from the state of South Carolina.  He is the former chief judge of the South Carolina Court of Appeals (1983–1992) and was the 19th President of the College of Charleston (1992–2001).  In 2002, he was the Democratic candidate for the U.S. Senate seat left vacant after the retirement of Strom Thurmond.  He was defeated by the Republican candidate, U.S. Representative Lindsey Graham.

Tom LaBonge: Thomas J. "Tom" LaBonge (born October 6, 1953) is an American politician.  He was a member of the Los Angeles City Council representing the 4th district, serving from 2001 to 2015.  He won a special election to fill the seat left vacant by the death of long-time council member John Ferraro.  The district represents a wide diversity of incomes and neighborhoods.  At the time he was in office, he was the Chairman of the Arts, Parks, Health and Aging committee, Vice Chairman of the Transportation Committee and the Ad Hoc River Committee, and member of the Trade, Commerce & Tourism Committee, and the Ad Hoc on Recovering Energy, Natural Resources & Economic Benefit from Waste for L.A. (RENEW LA) in the city of Los Angeles.  He is a member of the Democratic Party.

Geoff Buckland: Geoffrey Frederick Buckland (born 10 November 1947), was an Australian Labor Party member of the Australian Senate from 2000 to 2005, representing the state of South Australia.  Buckland was selected by the Parliament of South Australia to fill the Senate seat left vacant after the resignation of John Quirke under Section 15 of the Australian Constitution.  He was born in Sydney, New South Wales, and was blast furnace operator, and an official with the Federated Ironworkers' Association and later the Whyalla-Woomera Branch Secretary of the Australian Workers' Union before entering politics.

Barry Glassman: Barry Glassman (born March 24, 1962) is the current County Executive of Harford County, Maryland, elected to this position in 2014.  Formerly, he was a member of the Maryland State Senate, representing District 35 in Harford County, MD; he was appointed in 2008 to fill a vacancy, and subsequently was re-elected to the position in 2010.  Glassman was originally elected to the House of Delegates in 1998, along with Joanne S. Parrott, defeating incumbent Michael G. Comeau and winning the seat left vacant by James M. Harkins, who was elected as Harford County Executive.

Kathy Hochul: Kathleen Courtney "Kathy" Hochul (pronounced HOKE-ul; born August 27, 1958) is an American politician who is the current Lieutenant Governor of the State of New York.  She served previously as U.S. Representative for New York's 26th congressional district from June 1, 2011 to January 3, 2013.  She prevailed in the four-candidate special election of May 24, 2011, to fill the seat left vacant by the resignation of Republican Chris Lee, and was the first Democrat to represent the district in 40 years.

Mae Nolan: Mae Ella Nolan (September 20, 1886 – July 9, 1973) was an American politician who became the fourth woman to serve in the United States Congress, the first woman elected to Congress from California, the first woman to chair a Congressional committee, and the first to fill the seat left vacant by her husband's death.  She took her seat in the United States House of Representatives in 1923.

Supporting paragraphs: United States Senate election in Nevada, 2012 John Ensign
Answer: Dean Heller