Question: Which American professional baseball team that played in Metropolitan Stadium in 1970 had Ron Keller as a pitcher?

Context paragraphs:
Aaron Blair: Aaron Daniel Blair (born May 26, 1992) is an American professional baseball pitcher for the Atlanta Braves of Major League Baseball (MLB).  Blair attended Marshall University, where he played baseball for the Marshall Thundering Herd baseball team.  Prior to that, he attended Spring Valley High School in Spring Valley, Nevada and played for the school's baseball team.  The Houston Astros selected him in the 21st round of the 2010 Major League Baseball Draft but decided to go to college instead.  The Arizona Diamondbacks selected Blair with the 36th pick of the 2013 Major League Baseball Draft.  He was traded to the Atlanta Braves by the Diamondbacks as part of a five-player deal announced December 9, 2015.

Ron Keller: Ronald Lee Keller (born June 3, 1943) was a pitcher in Major League Baseball.  He played for the Minnesota Twins.

Simone Wearne: Simone Wearne (born 5 December 1980 in Melbourne) is a pitcher for the Australia women's national baseball team.  In the 2006 Women's Baseball World Cup she was named in the All-Star team as a pitcher.  She was a member of the Australian team which won the 2002 Women's World Baseball Series.  She is the sister of professional baseball infielder Scott Wearne.  She now (2013) plays and coaches teams for a baseball team called the Springvale Lions.  She is also coaching the women's national team, Victoria Blue, alongside Jade Hough.

Kuo Lee Chien-fu: Kuo Lee Chien-Fu (; born March 24, 1969 in Taoyuan County, Taiwan (now Taoyuan City)) is a retired Taiwanese professional baseball pitcher and currently a baseball coach.  He is best known for being the ace pitcher in the Chinese Taipei national baseball team in the 1992 Olympics where he was twice the winning pitcher in the two Chinese Taipei versus Japan matches, one in the preliminary round and the other in the semifinal.  The two victories helped the Chinese Taipei team win the silver medal that year.  He was also a member of the Chinese Taipei national baseball team in the 1988 Olympics when baseball was a demonstration sport, but did not play in any of the tournament's matches due to his juniority at that time.

Minnesota Twins: The Minnesota Twins are an American professional baseball team based in Minneapolis, Minnesota.  The Twins compete in Major League Baseball (MLB) as a member club of the American League (AL) Central division.  The team is named after the Twin Cities area comprising Minneapolis and St. Paul.  They played in Metropolitan Stadium from 1961 to 1981 and the Hubert H. Humphrey Metrodome from 1982 to 2009.  They played their inaugural game at the newly completed Target Field on April 12, 2010.

Metropolitan Stadium: Metropolitan Stadium (often referred to as "the Met", "Met Stadium", or now "the Old Met" to distinguish from the Metrodome) was a sports stadium that once stood in Bloomington, Minnesota, just outside Minneapolis.  The Minneapolis Millers minor league baseball team played at Met Stadium from 1956 to 1960.  The Minnesota Twins and the Minnesota Vikings then played at the "Met" from 1961 to 1981.  The North American Soccer League soccer team Minnesota Kicks also played there from 1976 to 1981.

Bill Pleis: William Pleis III (born August 5, 1937 in Kirkwood, Missouri) is a retired American professional baseball player, a left-handed pitcher who appeared in 190 Major League games between 1961 and 1966 for the Minnesota Twins.  On April 22, 1961, Pleis notched the Twins' first-ever win in their new home state and home field, Metropolitan Stadium.

Bob Welch (baseball): Robert Lynn Welch (November 3, 1956 – June 9, 2014) was an American professional baseball starting pitcher.  He played in Major League Baseball (MLB) for the Los Angeles Dodgers (1978–87) and Oakland Athletics (1988–94).  Prior to his professional career, he attended Eastern Michigan University, where he played college baseball for the Eastern Michigan Hurons baseball team.  He helped lead the Hurons, coached by Ron Oestrike, to the 1976 College World Series, losing to Arizona in the Championship Game.

Andrew Miller (baseball): Andrew Mark Miller (born May 21, 1985) is an American professional baseball relief pitcher for the Cleveland Indians of Major League Baseball (MLB).  He previously played for the Detroit Tigers, Florida Marlins, Boston Red Sox, Baltimore Orioles, and New York Yankees.  In 2017, he earned his first major championship in the World Baseball Classic as a member of the United States national baseball team.  Miller attended the University of North Carolina (UNC) at Chapel Hill and played college baseball for the Tar Heels before the Detroit Tigers drafted him.  After beginning his MLB career primarily as a starting pitcher, Miller converted to full-time relief in 2012, serving in middle relief, setup and closer roles.  He has pitched in three playoffs while his clubs have appeared in five.  At UNC, he won the "Baseball America" College Player of the Year and Roger Clemens Awards.  In his Major League career, he has been an All-Star selection, and has won the American League (AL) Reliever of the Year and the AL Championship Series Most Valuable Player Awards (ALCS MVP).

Rob Derksen: Robert William Derksen (January 12, 1960 – June 16, 2004) was an American professional baseball pitcher, coach, manager and scout, who also was an influential figure in international baseball.  Derksen was the head coach of the 1996 Australian Olympic Men's Baseball Team, the 2000 Guam National Baseball Team, and, at the time of his death, the 2004 Greek Olympic Men's Baseball Team.

Supporting paragraphs: Ron Keller Minnesota Twins
Answer: Minnesota Twins