Both teams have endured disappointing starts to the qualifying campaign and occupy the bottom two positions in Group A after four games.
Wales beat Scotland 2-1 in Cardiff back in October and Celtic midfielder Ledley is ready for a tough encounter in what will be Gordon Strachan's first competitive fixture as coach of the hosts.
"We know it's a derby and they're going to be up for it," Ledley told Sky Sports. "It will be a good atmosphere.
"With the players we've got, it's time for us to go on to a new level and move forward. I think it's going to be a battle, but hopefully we can play the right way, keep the ball on the floor and play from there."
Gareth Bale scored both goals in the victory back in the autumn and Ledley acknowledged the Tottenham Hotspur winger's importance to Wales.
Ledley added: "You can see his confidence is high and his ability has gone on to the next level. He's a gifted footballer.
"He's got pace, he's powerful, his dribbling is second to none, he can get at defenders both ways and his delivery is one of the best. Plus he can finish. I think he's the finished article.
"With Craig Bellamy back on the scene as well it's fantastic news for the players. To play with them is a massive confidence boost."
Though Scotland have picked up just two points from their four qualifiers, Ledley is aware of the threat posed by Strachan's charges.
"I think they've got a great squad," he continued. "If you look at the team and the players they've got, the majority of them this season have been playing in the Premier League or the Champions League.
"We've got to be careful with them because they are dangerous going forward."