Question: Which floor leader sponsored the Tarrif Act?

Context paragraphs:
Antonio Tinio: Antonio "Tonchi" Tinio is a Filipino activist and member of the House of Representatives (congressman), sitting as representative of ACT Teachers Partylist from the 15th to the 17th (current) Congress, serving as Assistant Minority Floor Leader in the 15th Congress.

Dale DeWitt: Dale DeWitt (born January 17, 1950) is a United States politician from Oklahoma.  DeWitt currently serves in the Oklahoma House of Representatives.  He served as Majority Leader and Majority Floor Leader during 2011 and 2012.

Minority leader: In U.S. politics, the minority leader is the floor leader of the second largest caucus in a legislative body.  Given the two-party nature of the U.S. system, the minority leader is almost inevitably either a Republican or a Democrat.  The position could be considered similar to that of the Leader of the Opposition in Parliamentary systems.  In bicameral legislatures, the counterpart to the minority leader in the lower house is the Speaker, and the majority leader is hence only the second-most senior member of the majority caucus.  Contrastingly, in upper houses the titular Speaker is frequently a separately elected officer such as a lieutenant governor or vice president.

Revenue Act of 1913: The Revenue Act of 1913, also known as the Tariff Act, the Underwood Tariff, the Underwood Act, the Underwood Tariff Act, or the Underwood-Simmons Act (ch.  16, 38 Stat.  114 , October 3, 1913), re-imposed the federal income tax after the ratification of the Sixteenth Amendment and lowered basic tariff rates from 40% to 25%, well below the Payne-Aldrich Tariff Act of 1909.  It was signed into law by President Woodrow Wilson on October 3, 1913 and was sponsored by Alabama Representative Oscar Underwood.

John Wesley Fribley: John Wesley Fribley was born on a farm near Assumption, Illinois, in 1906, and died in Shelbyville, Illinois, in 2002.  He represented the 40th Senate District in the Illinois State Senate from 1934 through 1952.  He had significant legislative achievements in transportation, oil and gas regulation, and mine safety.  He helped investigate the Centralia mine disaster and was co-sponsor of the Illinois Mine Safety Law.  He sponsored the Farm-to-Market Road Law, which constructed township roads and benefited rural towns in Central Illinois.  He worked to improve the relationship between Chicago and downstate Illinois.  Fribley was a downstate floor leader for former Governor Adlai E. Stevenson.

James Allen Williamson: James Allen Williamson (born May 27, 1951) is an American attorney and Republican politician from the U.S. state of Oklahoma.  Williamson served in the Oklahoma House of Representatives from 1980 to 1986 and in the Oklahoma Senate from 1996 to 2008.  From 1998 to 2002 he served as Assistant Republican Floor Leader, and then as Floor Leader from 2003 to 2004.

Oscar Underwood: Oscar Wilder Underwood (May 6, 1862 – January 25, 1929) was an American lawyer and politician from Alabama, and also a candidate for President of the United States in 1912 and 1924.  He was the first formally designated floor leader in the United States Senate, and the only individual to serve as the Democratic leader in both the Senate and the United States House of Representatives.

Party leadership of the United States Senate: The party leadership of the United States Senate refers to the officials elected by the Senate Democratic Caucus and the Senate Republican Conference to manage the affairs of each party in the See.  Each party is led by a floor leader who directs the legislative agenda of his caucus in the Senate, and who is augmented by an Assistant Leader or Whip, and several other officials who work together to manage the floor schedule of legislation, enforce party discipline; oversee efforts to elect new Senators, and maintain party unity.

Cynthia Thielen: Cynthia Henry Thielen (born September 22, 1933) is a member of the Hawaii House of Representatives representing District 50, the Kailua and Kaneohe Bay areas of Oahu County.  She is a Republican and has served in the state House of Representatives since 1990.  She served as minority floor leader from 1992 to 1997 and is the current assistant minority leader.

Thomas M. Hannigan: Thomas M. Hannigan served in the California State Assembly from 1978 until he was termed out in 1996.  From 1986 through 1995 he was the Majority Floor Leader in the Assembly.  He was a Democrat from Solano County.  Throughout his political career, Hannigan was a strong supporter of legislation supporting the protection and development of water resources.  He was a key proponent of Proposition 204, which voters approved in November 1996.  The Safe, Clean, Reliable Water Supply Act provided $995 million to fund water programs and statewide levees.

Supporting paragraphs: Revenue Act of 1913 Oscar Underwood
Answer: Oscar Underwood