National Democrats and Republicans are paying attention to the Indiana Senate race.The Democratic Senatorial Campaign Committee spent $250,000 on a television ad to back Congressman Joe Donnelly against Republican Richard Mourdock.The 30-second spot goes after Mourdock for saying the highlight of politics is to "inflict" his views on others, calling Social Security "unconstitutional" and alleges he wants to cut Medicare while giving "more tax breaks to Wall Street."Check it out:Conservative super PACs are also spending money in Indiana.Donnelly is being attacked by a much larger $620,000 ad buy from American Crossroads GPS, which is backing GOP candidates across the country.The National Republican Senatorial Committee has chimed in as well, running a web ad questioning Donnelly's record and if he voted for Nancy Pelosi, D-Calif., as speaker.Check that out: