I agree with the first answer, but I think that a full answer to the question needs to include the differences between Roosevelt's New Nationalism and Wilson's New Federalism.
Both candidates wanted the basic progressive goal of taking power from the rich and the big companies and giving it to the middle classes. But the two of them disagreed on the proper way to do this.
TR believed that big business was a permanent thing and so there needed to be big government to regulate it. Wilson believed that big government should exist only for as long as it took to break big business and create an economic system that emphasized smaller businesses.
This shows that there were at least a couple of different ways to pursue Progressive goals.
1912 was a pivotal and interesting election because of the variety of serious candidates involved in that race. Wilson, the Democrat, represented a move towards Progressivism for that party, but socially represented more of the status quo of the time. William Howard Taft was the Republican incumbent who was supposed to represent progressive advances, but had mostly only gone after the trusts. Teddy Roosevelt formed his own Progressive "Bull Moose" Party to try and reclaim the "true" progressive label, while Eugene Debs represented the socialist point of view, and received a significant number of votes, though his party was already fading by that time.