Complex sentence: He served in South Africa's post-apartheid Senate from 1994 to 1997 as Deputy President of the Senate, and its successor, the National Council of Provinces from 1997 to 1999.
Split into simpler sentences: He served in South Africa's post-apartheid Senate from 1994 to 1997 as Deputy President of the Senate. He then served in the Senate's successor, the National Council of Provinces, from 1997 to 1999.