Question: Walter Leslie Duncan, director of the Adelaide Steamship Company, resigned from the Senate in what year?

Context paragraphs:
Alaska Steamship Company: The Alaska Steamship Company was formed on August 3, 1894.  While it originally set out to ship passengers and fishing products, the Alaska Steamship Company began shipping mining equipment, dog sleds, and cattle at the outbreak of the Klondike Gold Rush of 1897.  The company was purchased by the Alaska Syndicate and merged with the Northwestern Steamship Company in 1909, but retained its name, and the fleet was expanded to 18 ships.  During World War II, the government took over the company's ships.  When the war ended, the company struggled to compete with the new Alaska Highway for passengers and freight.  It discontinued passenger service altogether in 1954 and shut down operations in 1971.

Adelaide Steamship House: The Adelaide Steamship House is located at 10-12 Mouat Street, Fremantle.  Built in 1900, the building was designed by Fremantle based architectural firm Charles Oldham and Herbert Eales and was constructed by C. Coghill.  The building takes its name from the original owners of the building, the Adelaide Steamship Company, who provided sea passenger and freight services around Australia.

SS Oregon (1878): SS "Oregon" (1878–1906) was a coastal passenger/cargo ship constructed in Chester, Pennsylvania by the Delaware River Iron Ship Building and Engine Works in February 1878.  Originally delivered to the Oregon Steamship Company, she was used on the Portland, Oregon-to-San Francisco, California route for many years.  In 1879, the Oregon Railroad and Navigation Company became the "Oregon"′s new owners after purchasing the Oregon Steamship Company.  Also included in this purchase were the steamships "George W. Elder" and "City of Chester".  While in O.R. & N service, "Oregon" served alongside SS "Columbia", which made the first commercial use of Thomas Edison's incandescent light bulb.  Like "Oregon", "Columbia" was also built by John Roach & Sons in Chester, Pennsylvania.  Over time, "Oregon's" hull became breached after a number of incidents.  Furthermore, the hull had been weighted with concrete to the point where she was considered unsuitable for service as a passenger liner.  After operating as a cargo ship, she was laid up in 1894 at Portland.  In 1899, the "Oregon" was re-qualified to carry passengers once more.  She was sold by O.R. & N the same year.  Despite this, she was viewed as a cursed ship by her crew.  The "Oregon" was owned by the White Star Steamship Company (not to be confused with the White Star Line) from around 1902 to 1905 .  Around this time, "Oregon" was operating between Alaska and Puget Sound.

Adelaide Steamship Company: The Adelaide Steamship Company was formed by a group of South Australian businessmen in 1875.  Their aim was to control the transport of goods between Adelaide and Melbourne and profit from the need for an efficient and comfortable passenger service.  For the first 100 years of its life, the main activities of the company were conventional shipping operations on the Australian coast, primary products, consumer cargoes and extensive passenger services.

Pacific Coast Steamship Company: The Pacific Coast Steamship Company was an important early shipping company that operated steamships on the west coast of North America.  Organized in 1867 under the name of Goodall, Nelson and Perkins the company.  The Goodall, Nelson & Perkins Steamship Company was formed in 1875, but a year later reorganized as the Pacific Coast Steamship Company.  In 1916 the Admiral Line bought the shipping interests of the company.

Inman Line: The Inman Line was one of the three largest 19th-century British passenger shipping companies on the North Atlantic, along with the White Star Line and Cunard Line.  Founded in 1850, it was absorbed in 1893 into American Line.  The firm's formal name for much of its history was the Liverpool, Philadelphia and New York Steamship Company, but it was also variously known as the Liverpool and Philadelphia Steamship Company, as Inman Steamship Company, Limited, and, in the last few years before absorption, as the Inman and International Steamship Company.

David Charleston: David Morley Charleston (27 May 1848 – 20 June 1934) was an Cornish-born, Australian politician.  Born in St Erth, Cornwall, he received only a primary education before becoming an apprentice engineer, and later an engineering unionist and marine engineer.  Migrating to Australia in 1884, he continued his engineering work with the Adelaide Steamship Company, but resigned in 1887 after labour troubles.  He subsequently became President of the Adelaide Trades and Labour Council.

HMAT Wandilla: SS "Wandilla was a steamship built in 1912 for the Adelaide Steamship Company.  The ship operated on the Fremantle to Sydney run until 1915, when she was acquired for military service and redesignated HMAT "Wandilla.  Initially used as a troop transport, the vessel was converted to a hospital ship in 1916.  "Wandilla" was returned to her owners at the end of the war, then was sold to the Bermuda & West Indies SS Company and renamed Fort St. George in 1921.  She was sold in 1935 to Lloyd Triestino and renamed Cesarea before being renamed Arno in 1938.  At the start of World War II, the ship was acquired by the Regia Marina for use as a hospital ship.  She was sunk by British aircraft on 10 September 1942.

SS Penola: SS "Perth", formerly SS "Penola" was a  GRT steamship operated by the Adelaide Steamship Company.  "Penola" was notable for ramming and sinking the SS City of Launceston, a passenger steamship, in Port Phillip Bay on 19 November 1865.  Renamed "Perth", the steamship ran aground and was wrecked off Point Cloates in Western Australia on 17 September 1887.

Walter Leslie Duncan: Walter Leslie Duncan (14 February 1883 – 28 May 1947) was an Australian politician.  Born in Armidale, New South Wales, he was educated at state schools before becoming a clerk, and was President of the Labor Council of New South Wales in 1911.  A member of the Labor Party, he joined the Nationalists in the wake of the 1916 split over conscription.  Duncan enlisted in the military in 1917, leaving in 1919 to successfully contest the Senate for the Nationalists.  A strong supporter of Billy Hughes, he was excluded from the party along with Hughes in 1929 and joined the Australian Party, before being reaccepted into the United Australia Party in 1931.  He resigned from the Senate in 1931.  He was also a Director of the Adelaide Steamship Company for many years.  Duncan died in 1947.

Supporting paragraphs: Walter Leslie Duncan Adelaide Steamship Company
Answer: 1931