Complex sentence: She took over fellow Republican Hamilton Fish IV's seat after he dropped out of the 1994 race due to prostate cancer, beating his son, and remained in office until she was defeated in the 2006 congressional election by John Hall.
Split into simpler sentences: She took over fellow Republican Hamilton Fish IV's seat after he dropped out of the 1994 race due to prostate cancer. Kelly defeated his son, Hamilton Fish V, in that race and remained in office until she was defeated in the 2006 congressional election by John Hall.