Question: The 17th Premier of Nova Scotia and leader of the federal Progressive Conservative Party of Canada Robert Stanfield fought a few times and lost in general elections against which politician who is currently one of the longest-serving Prime Minister in Canadian history?

<P0-S0> Halifax Stanfield International Airport (IATA: YHZ, ICAO: CYHZ) is a Canadian airport located in Enfield, Nova Scotia, an area of Halifax, Nova Scotia. <P0-S1>  It serves Halifax, mainland Nova Scotia and adjacent areas in the neighbouring Maritime provinces. <P0-S2>  The airport is named in honour of Robert Stanfield, the 17th Premier of Nova Scotia and leader of the federal Progressive Conservative Party of Canada. <SEP> <P1-S0>  He was born into an affluent Nova Scotia clothing manufacturing and political family in 1914. <P1-S1>  He graduated from Dalhousie University and Harvard Law School in the 1930s. <P1-S2>  Stanfield became the leader of the Nova Scotia Progressive Conservative Party in 1948, and after a rebuilding period, led the party to government in 1956. <P1-S3>  As premier, he won three straight elections. <P1-S4>  His government was credited with modernizing the way the province delivered education and medical services. <P1-S5>  In 1967, he resigned as premier and became the leader of the federal Progressive Conservative Party. <P1-S6> Robert Lorne Stanfield, PC, QC (April 11, 1914 – December 16, 2003) was the 17th Premier of Nova Scotia and leader of the federal Progressive Conservative Party of Canada. <P1-S7>  He was the leader of the "Her Majesty's Loyal Opposition" and fought three general elections, losing each time to the Liberals under Pierre Trudeau. <P1-S8>  He resigned as leader in 1976 and from public office in 1979. <P1-S9>  In retirement, he lived mostly in Ottawa, and died there in 2003 from complications due to pneumonia. <P1-S10>  He is sometimes referred to as "the best prime minister Canada never had". <P1-S11>  As one of Canada's most distinguished and respected statesmen, he was one of several people granted the style "The Right Honourable" who were not so entitled by virtue of an office held. <SEP> <P2-S0>  He is the 3rd longest-serving Prime Minister in Canadian history (behind William Lyon Mackenzie King and John A. Macdonald), having served for 15 years, 164 days. <P2-S1> Joseph Philippe Pierre Yves Elliott Trudeau, ( ; ] ; October 18, 1919 – September 28, 2000), often referred to by the initials PET, was a Canadian statesman who served as the 15th Prime Minister of Canada (1968–1979 and 1980–1984). <SEP> <P3-S0> Peter Gordon MacKay {'1': ", '2': ", '3': ", '4': "} (born September 27, 1965) is a lawyer and politician from Nova Scotia, Canada. <P3-S1>  He was a Member of Parliament from 1997 to 2015 and has served as Minister of Justice and Attorney General (2013–2015), Minister of National Defence (2007–2013), and Minister of Foreign Affairs (2006–2007) in the Cabinet of Canada under Prime Minister Stephen Harper. <P3-S2>  MacKay was the final leader of the Progressive Conservative Party of Canada (PC Party), and he agreed to merge the party with Stephen Harper's Canadian Alliance in 2003, forming the Conservative Party of Canada.