Who usually benefits the most from gerrymandering congressional districts?

From the past, the Republican party has been the biggest advantage when we talk about gerrymandering. Gerrymandering allows small pockets of people to gain greater influence in their area, even if they are in the minority on a larger scale.

 Gerrymandering typically benefits whichever political party has the majority in the legislature at the time the congressional district lines are redrawn.

Context / history:

The landmark case regarding voting district lines was Baker v. Carr (1962), which pertained to voting districts in Tennessee.  The plaintiff, Charles Baker, argued that voting districts, which had not been redrawn since 1901, heavily favored rural locations over urban centers which had grown significantly since then.  Joe Carr was Secretary of State for Tennessee at the time, so was named in the case in regard to voting district lines as drawn by the state legislature.  The Supreme Court ruled that voting districts were not merely a political matter to be decided by legislatures, but that they were subject to review by federal courts to determine their fairness. 

The matter of redrawing district lines has come up in court cases again recently as some state legislatures, when dominated by one political party, have "gerrymandered" district lines to try to maintain continued prominence for their party.   In the present political context, this has given the Republican Party an advantage in the overall voting balance in the country.  

after the civil war, and with the termination of slavery, the south was faced with a big problem; what was supposed to happen and how they were supposed to deal with the freedom and the rights that black people and freed slaves had gained as a result of the north defeating the south and forcing the end of slavery. first, most, if not all, of the workforce of the south came from slaves and they did not have an option to replace the loss of said workforce. second, particularly in the south, people were convinced that black people were lesser, less intelligent, less capable and less smart than whites. this posed a huge problem for them. also, southerners were faced with another issue; freed slaves now had a say in how their lives would be lived and the right to politically choose the way they would be governed. people in the south did not want to accept this, none of this and this opposition and the conflicts that arose from it, not to mention the afereffects of the war, forced the congress of the time to enact and enforce the reconstruction plans that had been proposed by president andrew johnson.