Rep. Ann Kirkpatrick is battling Republican Brandon Martin in Arizona's 2nd Congressional District.
The district is located in the Southeast of the state and encompasses about two-thirds of the city of Tucson.
According to Business Insider, the district was previously represented by Sen.Marth McSally.
The Center for Responsive Politics reported that Kirkpatrick has raised $1.7 million, and spent around $957,000 in her bid.
Martin has raised approximately $336,000 and spent $315,000.
The latest polling numbers show Kirkpatrick in the lead with 60.85% of the votes reported.