ACCRA (AFP) - John Atta-Mills, 64, will be the next leader of Ghana, the electoral commission declared Saturday as it announced the outcome of a presidential run-off in the West African nation. Atta-Mills, running under the banner of the National Democratic Congress (NDC), took 50.23 percent of the vote, against 49.77 percent for his rival Nana Akufo-Addo, 64, of the governing New Patriotic Party (NPP). "On the basis of the official results given, it's my duty to declare Professor John Evans Atta-Mills president-elect of the Republic of Ghana," electoral commissioner Kwado Afari-Gyan told reporters. "Victory for the opposition party is a victory for democracy," NDC member Sekou Nkrumah, the youngest son of Ghana's first president at independence Kwame Nkrumah, told AFP at the party's headquarters. "After eight years in the wilderness, the NDC is back to build a better Ghana", he said. A spokesman for the ruling NPP said Akufo-Addo would react to the electoral commission's statement later in the day. Meanwhile, NDC supporters in white-campaign t-shirts thronged the streets of Accra, cheering and honking car horns. NDC won a majority of parliamentary seats in legislative elections that held December 7. NDC is now the largest party in the 230-seat parliament with 114 seats, against 107 for the NPP. Atta-Mills, a law professor, was running for president for the third time; he lost the previous two elections to outgoing President John Kufuor. He served as vice president to the charismatic former leader Jerry Rawlings from 1997 to 2000. Referring to complaints raised by both political parties over the conduct of polling in certain regions, Afari-Gyan said: "The commission did not find the evidence provided sufficient to invalidate the result". He said final results were reached by adding the votes garnered by each candidate in Tain, a western Ghana constituency that voted Friday, to results from the other 229 constituencies that cast their second-round votes on December 28. Atta-Mills won Tain by a wide margin. Akufo-Addo had won an inconclusive first round of nation-wide voting on December 7. His political party had called upon its supporters to boycott the voting in Tain. Akufo-Addo, a former justice minister and then foreign minister, was running for the presidency for the first time. Ghana, regarded as a beacon of democracy in West Africa, will start pumping oil in 2010. The elections were its fifth since a return to multi-party democracy in 1992. Some 12.5 million people were eligible to cast ballots in the polls which were closely watched throughout as a litmus test of whether Ghana has truly consolidated its democracy. Last month Guinea, Africa's second-oldest independent state, was rocked by a bloodless coup, moments after the death of a its longtime president Lansana Conte. Mauritania's first democratically elected leader was ousted in a coup in August.