Akame takes this easily, Murasame is waaaay too OP. Let me see the points :
a) Speed : Zoro was as fast as Pre-Timeskip Luffy Gear 2, but Akame moved so fast she killed 3 Tribal Assassins before they even realized what happened, also she Moved so fast that Zank's Teigu which can literally read minds and predict movements (Also see through her clothes ( ͡° ͜ʖ ͡°) ) could not keep up. And if Zank's Teigu could not keep up, you can bet Zoro's Observation Haki (which as many have stated above, is unreliable and works only half the time) cannot keep up. Oh and all of this is not including her Trump Card, which boosts her speed even more. But since here it is mentioned that speed is equalized, this is just a wash
b) Experience : Both Akame and Zoro have trained with weapons since a very young age, but honestly Akame had it worse, when she was in her pre-teens she had to manage to make it out of a forest infested with Danger Beasts (who were shown to have been eating other children), she and Kurome managed to hold off the beasts and slew them, when she was practically 10 years old...she was shown to be an expert at weilding her Shingu Kiriichimonji and later her Teigu Murasame and she killed her first victim in her preteens as well
c) Swords Skills : Zoro trained with Mihawk and is now practically the strongest swordsman in the One Piece verse (barring Mihawk himself), he has created two fighting styles on his own, Santoryuu and Kyutoryuu,cut Pica in half with one strike. Akame has shown to be a master at weilding her swords, even doing stuff like breaking metal by striking it repeatedly with her sword in one place, so even armor like Armamnent Haki would serve little aid to Zoro. She is a good at hand-to-hand as well, seeing as she out-paced Ibera and snapped his neck with only her legs, but still I would give this to Zoro just because of the sheer length of One Piece has allowed more of his feats to be shown.
I could go on, but at the end of the day Akame only needs one strike to win....and tbh the Murasame's poison having no antidote thing should be restricted to the Akame ga Kill verse. If not, then that would be like saying she can beat Goku, Superman or Drago if she manages to get a hit on them....