Original: He was twice elected as Prime Minister of Pakistan, serving two non-consecutive terms, the first from November 1, 1990 to July 18, 1993 and the second from February 17, 1997 to October 12, 1999.
Simplified: His first time as prime minister was from November 1, 1990 to July 18, 1993. The second was from February 17, 1997 to October 12, 1999.