Bidding adieu to the 112th Congress -- by the numbers the least productive and least popular of the modern era -- today marks the start of a 113th Congress marked both by its inherited challenges as its noteworthy firsts.

Democratic Leader Nancy Pelosi stands with the Democratic women of the House to highlight the historic diversity of the House Democratic Caucus, on January 3, 2013 in Washington, DC.

With the outgoing Congress facing rock-bottom approval ratings and having passed the lowest number of bills (about 220) since the 1940s, the new crop is already slated to face bruising battles over the federal deficit and spending.

And while a great many of those serving the previous two years are returning, the 113th Congress' class of more than 90 new lawmakers features plenty of historical firsts, including enough new women, LGBT members, Asian Americans and Latinos to set records.

There are 82 new members of the House -- 35 Republicans and 47 Democrats -- and 13 new senators, including appointee Tim Scott, R-S.C., who will be the upper chamber's only African-American.

While losing some of its most senior and well-known members, including conservative leader Sen. Jim DeMint and independent Sen. Joe Lieberman, the Senate today welcomes new faces who bring historic firsts with their swearings-in.

Scott, an appointee who replaces DeMint, will be the first black senator from the South since Blanche Bruce of Mississippi in 1881 and the first Republican African-American senator since the 1970s.

Republican Ted Cruz, a Cuban-American who beat Texas's lieutenant governor in an upset primary, is the first Latino to represent the diverse state of Texas in the Senate.

Massachusetts' Elizabeth Warren, who became a folk hero among financial system reformers after the financial crisis, will sit on the Senate's banking committee. She's one of a record 20 women in the new Senate.

Democrat Tammy Baldwin of Wisconsin, who defeated Republican Gov. Tommy Thompson, will be the first openly gay senator.

Six of the new senators came from service in the U.S. House, including former Rep. Mazie Hirono of Hawaii, the first Asian-American woman to serve in the upper chamber. (She's also the first Buddhist.)

Arizona's Jeff Flake will join six other Mormon colleagues in the upper chamber.

All told, the partisan breakdown will narrow slightly in Democrats' favor.

In the House, there will be a total of 233 Republicans, 200 Democrats, and two vacancies (likely to be filled by one Republican and one Democrat, respectively.)

In the Senate, Democrats will continue to control the Senate – but with a slightly larger 55-45 majority than the 112th, with two independents caucusing with the Democrats.

And as for their approval ratings? With only about one in 10 Americans giving Congress a thumbs up, there's little room left to go down.