QUITO, Aug 20 (Reuters) - Leftist candidate Luisa Gonzalez and surprise challenger, business scion Daniel Noboa, won the first round of Ecuador's presidential election, beating out six rivals in a race clouded by the murder of anti-graft candidate Fernando Villavicencio. Gonzalez, a protege of former President Rafael Correa who has promised to revive his social programs, was tallying 33% support, with more than 70% of ballot boxes counted, according to figures from the National Electoral Council. "We are celebrating because we are making history, even though so many of us have been ignored, today we begin moving toward a different...