Question: Republican challenger Rudolph Ely "Rudy" Boschwitz defeated what Democratic incumbent in the 1978 United States Senate election in Minnesota?

Context articles: United States Senate election in Indiana, 2010
United States Senate election in Minnesota, 1984
United States Senate election in Delaware, 1978
Josh Mandel
Rudy Boschwitz
United States Senate election in Montana, 1978
United States Senate election in Minnesota, 1990
United States Senate election in Illinois, 1978
United States Senate election in Minnesota, 1978
New Jersey General Assembly elections, 2009

The 2010 United States Senate election in Indiana took place on November 2, 2010, alongside 33 other elections to the United States Senate in other states and elections to the United States House of Representatives and various state and local elections to fill Indiana's class III United States Senate seat.
 Incumbent Democratic U.S. Senator Evan Bayh decided in February 2010 to retire instead of seeking a third term shortly after former U.S. Senator Dan Coats announced his candidacy for Bayh's contested seat.
 No Democratic candidate submitted enough signatures by the deadline to run, leading Democratic officials to choose U.S. Congressman Brad Ellsworth to be the nominee.
 The Libertarian Party nominated YMCA instructor Rebecca Sink-Burris, who had previously run against Evan Bayh in the United States Senate election in Indiana, 1998 but with less success than in this election.
 Republican nominee and former U.S. Senator Dan Coats won the open seat.
The 1984 United States Senate election in Minnesota was held on November 6, 1984.
 Incumbent Republican U.S. Senator Rudy Boschwitz defeated Democratic challenger Joan Growe.
The 1978 United States Senate election in Delaware was held on November 7, 1978.
 Incumbent Democratic United States Senator Joe Biden won re-election to a second term, defeating Republican challenger James H. Baxter Jr..
Joshua A. Mandel (born September 27, 1977) is an American Republican politician who is the incumbent State Treasurer of Ohio.
 Mandel has held elected office since 2003: as a city councilman, from 2003 to 2007; as a member of the Ohio House of Representatives, from 2007 to 2011; and as state treasurer since 2011.
 He was the Republican challenger to incumbent Senator Sherrod Brown in the 2012 U.S. Senate election in Ohio, but was defeated.
 In 2016, he announced his intention to again challenge Brown in the 2018 U.S. Senate election in Ohio.
Rudolph Ely "Rudy" Boschwitz (born November 7, 1930) is a former Independent-Republican United States Senator from Minnesota.
 He served in the Senate from December 1978 to January 1991, in the 96th, 97th, 98th, 99th, 100th, and 101st congresses.
 He was then defeated by Paul Wellstone.
The 1978 United States Senate election in Montana took place on November 7, 1978.
 Following the death of United States Senator Lee Metcalf on January 12, 1978, Montana Supreme Court Chief Justice Paul G. Hatfield was appointed to serve for the remainder of Metcalf's term.
 Hatfield opted to run for re-election, but was overwhelmingly defeated in the Democratic primary by United States Congressman Max Baucus of the 1st congressional district.
 Baucus advanced to the general election, where he was opposed by Larry R. Williams, an author and the Republican nominee.
 Baucus ended up defeating Williams by a solid margin to win his first term in the Senate, and, following Hatfield's resignation on December 12, 1978, he began serving his first term in the Senate.
The 1990 United States Senate election in Minnesota was held on November 6, 1990.
 Incumbent Republican U.S. Senator Rudy Boschwitz was defeated by Democratic challenger Paul Wellstone in a tight race.
 Widely considered an underdog and outspent by a 7-to-1 margin, Wellstone was the only candidate to defeat an incumbent senator in the 1990 election cycle and gained national attention after his upset victory.
The 1978 United States Senate election in Illinois took place on November 7, 1978.
 Incumbent Republican United States Senator Charles H. Percy ran for re-election to a third term in the United States Senate.
 Percy was opposed by Democratic nominee Alex Seith, an attorney who had been appointed to several local government positions.
 Though Percy had been expected to coast to re-election over Seith, a first-time candidate, the election quickly became competitive.
 In the last few days of the campaign, a desperate Percy ran a television advertisement that featured him apologizing and acknowledging that, "I got your message and you're right."
 Percy's last-ditch effort appeared to have paid off, as he was able to edge out Seith to win what would end up being his third and final term in the Senate.
The 1978 United States Senate election in Minnesota was held on November 7, 1978.
 Incumbent Democratic U.S. Senator Wendell Anderson was defeated by Republican challenger Rudy Boschwitz.
The 2009 New Jersey General Assembly elections were held on November 3, 2009 for all 80 seats in the lower house of the New Jersey Legislature.
 Voters in New Jersey's 40 legislative districts cast 4,204,034 votes, two votes per person.
 The Democratic Party won a 47-seat majority while losing the popular vote.
 The Republican Party won a majority of votes cast but received only a 33-seat minority, an increase of 1 seat from their 2007 election results.
 The election coincided with a gubernatorial election where Democratic incumbent Governor Jon Corzine was defeated by Republican challenger Chris Christie.