Brazil's election headed for runoff

• NEW: Exit polls say incumbent Dilma Rousseff is headed for a runoff


• NEW: With nearly 88% of votes counted, she has nearly 41% of votes


• Rousseff is Brazil's first female President and was once a Marxist rebel

Sao Paulo, Brazil (CNN) -- Brazil's presidential vote is headed for a runoff.

Preliminary election results from the South American country show President Dilma Rousseff in the lead. But she didn't get the majority necessary to win in the first round.

With nearly 88% of votes counted, Rousseff had 40.68% of votes, Brazil's Supreme Electoral Court said. Aecio Neves was in second place with 34.71%. And Marina Silva was in third place with 20.99%.

Exit polls Sunday indicated there would be a runoff between Rousseff, the incumbent, and Neves, a center-right candidate. In a poll conducted by the Ibope public research firm, Rousseff won 44% of votes, Neves won 30% and Silva won 22%.

Silva, the candidate for the Brazilian Socialist Party, had gained momentum and backing from a growing number of supporters leading up to the vote, with polls before the election placing her in second place. She joined the race after candidate Eduardo Campos died in a plane crash.

Rousseff, 66, was once a Marxist rebel who was allegedly tortured in the early 1970s during Brazil's former dictatorship.

With her trademark pixie-short hair style and thick glasses, she became one of most Brazil's most wanted fugitives, branded by some as a "subversive Joan of Arc."

She has a solid track record in running the executive office. Before becoming president in 2011, Rousseff, from the Workers' Party, was chief of staff to former President Lula da Silva.

She democratized Brazil's electricity sector through the "Luz Para Todos" (Light for All) program, which made electricity widely available, even in rural areas.

Rousseff presided over the soccer World Cup in Brazil, but she took a lot of political flack over how public money was spent.

Streets filled with hundreds of thousands of demonstrators questioning the morality of pumping so much money into stadiums instead of programs to fight poverty and build infrastructure.

Rousseff defended the spending, saying the vast majority of funds earmarked for infrastructure projects were spent on projects for the nation, not the soccer tournament.

And Rousseff claims that under the presidencies of her predecessor and herself, masses of Brazilians have risen out of poverty.

"We have also mainstreamed into the middle class no less than 42 million people," she has said.

But inflation is now weighing down that progress.

Rousseff takes conservative stances on some women's issues. "I am against abortion, I am pro-life," she told Aparecida TV, a Catholic network. But she has pledged to fight for gay rights.

CNN's Shasta Darlington reported from Sao Paulo, Ben Brumfield reported and wrote from Atlanta. CNN's Catherine E. Shoichet contributed to this report.