Complex sentence: The special election took place on April 18,2017, with Republican Karen Handel defeating Gray and heading for a run-off election on June 20,2017 against Democrat Jon Ossoff.
Split into simpler sentences: The special election took place on April 18,2017. Then group's bid wasn't unsuccessful as Karen Handel beat Gray and headed for a run-off election on June 20,2017 against Jon Ossoff.