City Native Elected JudgeRussell Mittelstadt, 35, Madison, a native of Gau Claire, was elected as judge of the general branch of Dane County Cdurt, Tuesday. He is the son of Mrs. Pearl Mittelstadt, 820 Graham Ave., and his wife is the former Marlys Rudd, whose mother, Mrs. Mabel Rudd lives at 302 Mappa St.Mittelstadt defeated James W. Cassidy, family court commissioner, by 2,621 votes, 20,-389 to 17,768. He had been defeated in previous bids for the county judgeship and for district attorney.Mittelstadt’s term will begin Jan. 1, at a salary of $20,500 and a Madison newspaper reported it is likely Gov. Warren Knowles will appoint him to fill the post on June 1 when it is vacated by County Judge William Sachten who was elected to the circuit court in the sameelection.Mittelstad has been in private law practice in Madison since his graduation from the U n i-versity of Wisconsin Law Schoolin 1960.