Of which party was Nelson Mandela elected the leader in 1991?

Explanation

The former South African President Nelson Rolihlahla Mandela (1918-2013) was one of his country's foremost anti-apartheid activists. He spent his childhood in the Kingdom of Thembu and later started a legal career. In 1961 he became the leader of the ANC's armed wing, but was imprisoned a year later. He served 27 years in prison until his release in 1990. Afterwards, Mandela was elected the first black president of South Africa and received the Nobel Peace Prize alongside the previous President F.W. de Klerk in 1993.