Question: In what county is the city where William Tubby was born?

full_context: Document 1: Saylorville, Iowa: Saylorville is a census-designated place (CDP) in Polk County, Iowa, United States. The population was 3,301 at the 2010 census. It is part of the Des Moines–West Des Moines Metropolitan Statistical Area. The Saydel Community School District is located in this area. The unincorporated community of Marquisville is in this area.
Document 2: Tubby's: Tubby's is an American restaurant chain and franchise based in Clinton Township, Michigan, a suburb of Detroit, Michigan. Founded in 1968 in nearby St. Clair Shores, the chain operates more than 70 stores throughout Michigan, primarily in the Detroit metropolitan area. The chain primarily serves submarine sandwiches and salads, along with soft drinks, french fries and soup, and is known for its grilled subs.
Document 3: Indianola, Iowa: Indianola is a city in Warren County, Iowa, United States, 18 miles south of Des Moines, Iowa. The population was 14,782 at the 2010 census. It is the county seat of Warren County.
Document 4: New York City: New York has architecturally noteworthy buildings in a wide range of styles and from distinct time periods, from the saltbox style Pieter Claesen Wyckoff House in Brooklyn, the oldest section of which dates to 1656, to the modern One World Trade Center, the skyscraper at Ground Zero in Lower Manhattan and currently the most expensive new office tower in the world.
Document 5: Warren Platner: Born Joseph Warren Platner in Baltimore, Maryland, he graduated from Cornell University with a degree in architecture in 1941. His career began with work in some of the most prominent and remarkable architecture practices in the country. Between 1945 and 1950, he worked for Raymond Loewy and I.M. Pei.
Document 6: William R. Heath House: The William R. Heath House was designed by Frank Lloyd Wright, built in 1904–05, and is located at 76 Soldiers Place in Buffalo, New York. It is built in the Prairie School architectural style. It is a contributing property in the Elmwood Historic District–East historic district.
Document 7: Middletown, Iowa: Middletown is a city in Des Moines County, Iowa, United States. The population was 318 at the 2010 census. It is part of the Burlington, IA–IL Micropolitan Statistical Area.
Document 8: Kalona, Iowa: Kalona is a city in Washington County, Iowa, United States. It is part of the Iowa City, Iowa Metropolitan Statistical Area. The population was 2,363 at the 2010 census. Kalona is the second largest city in Washington County.
Document 9: Des Moines metropolitan area: The Des Moines metropolitan area, officially known as the Des Moines -- West Des Moines, IA Metropolitan Statistical Area (MSA), consists of five counties in central Iowa, United States: Polk, Dallas, Warren, Madison, and Guthrie. The 2010 census population of these counties was 569,633, and the 2017 estimated population was 645,911.
Document 10: Fort Dodge, Iowa: Fort Dodge is a city in and the county seat of Webster County, Iowa, United States, along the Des Moines River. The population was 25,206 in the 2010 census, an increase from 25,136 in the 2000 census. Fort Dodge is a major commercial center for North Central and Northwest Iowa. It is located on U.S. Routes 20 and 169.
Document 11: Colo, Iowa: Colo is a city in Story County, Iowa, United States. The population was 876 at the 2010 census. It is part of the Ames, Iowa Metropolitan Statistical Area, which is a part of the larger Ames-Boone, Iowa Combined Statistical Area.
Document 12: Max Taut: Max Taut was born in Königsberg, the younger brother of Bruno Taut. He, his brother and Franz Hoffman formed Taut & Hoffman, an architecture firm in Berlin, In the 1920s, Max Taut was particularly known for his office buildings for trade unions. Between 1922 and 1925, he built one house a year on Hiddensee island, each one very different from the others.
Document 13: William Tubby: Tubby was born in Des Moines, Iowa, and graduated from Brooklyn Polytechnic Institute in 1875. He worked in the architectural offices of Ebenezer L. Roberts until beginning his own firm in 1883. Continuing this practice until his retirement in 1942, Tubby became a major New York architect. He created important buildings in a variety of styles, and was especially known for his Romanesque and Dutch Revival-style designs.
Document 14: Franklin B. Ware: He was born in New York City in 1873, and received a degree in architecture from Columbia University in 1894. He entered practice with his father and brother in 1900 under the name James E. Ware and Sons. From 1901 to 1905, he was on the New York City Board of Aldermen. From 1907 to 1912, he served as State architect of New York. His father died in 1918, and he continued in practice with his brother. In addition to designing the White Plains Armory while State architect, in private practice his partnership designed the Huntington Gymnasium at Colgate University; Baggs Park Museum and Grace Church at Utica, New York; United States Post Office at Ossining, New York; buildings at Marymount University, Tarrytown, New York; the Grant Avenue Presbyterian Church, Plainfield, New Jersey; and a number of private residences in New York and New Jersey. While in practice with his father, they designed City and Suburban Homes Company's First Avenue Estate Historic District, added to the National Register of Historic Places in 1986.
Document 15: Corydon, Iowa: Corydon is a city in Wayne County, Iowa, United States. The population was 1,585 in the 2010 census, a decline from 1,591 in the 2000 census. It is the county seat of Wayne County.
ground_truth: Warren County
sub_queries: William Tubby >> place of birth Answer: Des Moines
Des Moines >> located in the administrative territorial entity Answer: Warren County