As of my last knowledge update in September 2021, there hasn't been a direct comparison of strength between Roronoa Zoro and Rob Lucci in the One Piece series. Both characters are powerful fighters in their own right, but their strengths can be influenced by various factors, including character development, training, and the plot's progression.
Rob Lucci is introduced as one of the main antagonists during the "Water 7" and "Enies Lobby" arcs. He is a member of the Cipher Pol 9 (CP9) organization and possesses the Rokushiki techniques, making him a formidable opponent. However, Zoro is one of the main protagonists and a member of the Straw Hat Pirates, known for his incredible swordsmanship and strength.
It's worth noting that in the One Piece world, power levels and strengths can shift due to character growth, new techniques, and the ongoing development of the story. Therefore, any direct comparison might be subject to change as the series continues.