Youths Heldat MadisonIMANITOWOC - The Madison Police Dept, is holding two juveniles from the Manitowoc1 area who were attempting to steal gasoline.Capt. Robert Schmidt of the Manitowoc Police Ddpt. Detective Bureau said Saturday that the boys, aged 15 and 17 years, had been missing from home for a period of time.He said that the 15-year-old Manitowoc youth, who is under the supervision of the Manitowoc County Welfare Dept., will be returned to the city Saturday by Donald Hillstrom, Manitowoc County sheriff.The 17-year-old, also being held in connection with the theft, is being held at Madison pending i disposition of his case.]