WASHINGTON, DC -- Democrats have held onto Gabrielle Giffords' Arizona congressional seat in Tuesday's by-election, quelling momentum for the Republicans heading into November's presidential contest.

But it's a short-lived prize.

Democrat Ron Barber, who was leading Republican Jesse Kelly 53 to 44% with 11% of precincts reporting at 11:30 p.m. ET, will only sit in Congress for five months. The two will square off again in November's congressional elections when all 435 seats in the House of Representatives are up for grabs.

Giffords suffered a non-fatal gunshot wound to the head 17 months ago in a shooting spree outside a Tucson grocery store. She resigned her seat in the House earlier this year to focus on her recovery.

Barber is a former Giffords aide who was also wounded in the Jan. 2011 shooting spree.

Kelly lost to Giffords by a razor-thin margin of 4,000 votes in 2010, and conservatives had been hoping to steal the seat from the Democrats in Tuesday's byelection.

While Barber had been trying to distance his candidacy from Giffords - repeating Tuesday a common mantra that it is "not Gabby's seat ... This is the people's seat" - the wildly popular Giffords and her astronaut husband began campaigning for Barber in recent days.

On Tuesday, Barber told reporters he was confident he'd campaigned as hard as he could.

"I don't think we've left any stone unturned," he said. "I've been all over the district since the day I announced my candidacy."

For their part, the Democrats tried hard to frame Kelly as a Tea Party extremist, highlighting statements he made in the 2010 election about needing to reform Medicare and social security -- both old age entitlement programs -- that proved unpopular in the increasingly ageing district. (It's actually the 11th oldest in the country.)

Kelly, meanwhile, kept his sights focused on the president and repeatedly linked Barber to Barack Obama, who has a relatively low (44%) approval rating in the state and is trailing GOP presidential candidate Mitt Romney by seven points, according to a recent poll.

"'Rubber stamp' Ron Barber is helping Obama, but he is hurting Arizona," warned Kelly in one television ad aired during the campaign, hinting Barber would blindly support the president's agenda.

Prior to Giffords winning the largely urban district in 2007, it had been held by Republicans for 22 years.

Some Democrats have been hinting about the party's chances of regaining a majority in the House of Representatives in November, which they lost to the GOP in 2010. To do so, they not only have to hold onto the seats they have now like Giffords', but they also need to steal 25 from the Republicans.

Republicans are keen themselves to hang onto their majority in the House, and also steal four Senate seats from the Democrats in November to gain a slim majority there, too.

One third of the Senate seats are also up for re-election in November.