The Democratic Congressional Campaign Committee has reserved at least $650,000 worth of TV air time for Denny Heck campaign commercials over the next eight weeks, the committee’s chairman confirmed Wednesday.U.S. Rep. Chris Van Hollen, D-Md., who chairs the DCCC and also serves as assistant House speaker, stopped off in Vancouver during a visit to the Northwest to promote Democratic candidates for Congress. He said the party is committed to spending “tens of millions of dollars” nationwide and to helping Heck defeat Republican Jaime Herrera in the race for the open 3rd Congressional District seat. “We see it as a competitive campaign that’s representative of races we see around the country,” Van Hollen said. “We believe Denny is a terrific candidate. In terms of doing everything we can to support his operation, we’ve reserved some TV time for him.”Van Hollen said it’s important that voters understand who is paying for the political ads they see on TV this election season.For example, he said, the conservative organization Americans for Prosperity, which recently bought $180,000 worth of TV ads supporting Herrera, is backed by Koch Industries, one of the nation’s largest and wealthiest companies, whose owners have benefited greatly from what he called “these perverse tax breaks” that reward companies for shipping American jobs overseas.Voters need to ask candidates if they agree with the political agendas of organizations that spend money independently on behalf of their campaigns, Van Hollen said.