Unbeaten Bayer Leverkusen retained a two-point lead over Bayern Munich into their Bundesliga table topper next week, with Leverkusen winning 2-0 at bottom side Darmstadt and Bayern beating Borussia Mönchengladbach 3-1 on Saturday. Nathan Tella scored a 33rd and 52nd minute brace as Leverkusen regrouped well from a 0-0 draw against Gladbach eight days ago. Gladbach led in Munich from Nico Elvedi in the 35th but the champions fought back from teenager Aleksandar Pavlovic in the 45th, league top scorer Harry Kane with his 24th goal in the 70th and Matthijs de Ligt in the 86th. Leverkusen host Bay…