Complex sentence: MacDonald lost his seat in the 1963 provincial election and the NDP would not win another until Jeremy Akerman became party leader and won the riding of Cape Breton East in the 1970 election.
Split into simpler sentences: MacDonald lost his seat in the 1963 provincial election. The NDP would not win another until Jeremy Akerman became party leader and won the riding of Cape Breton East in the 1970 election.