Around 42 per cent voters on Saturday exercised their franchise in the keenly watched by-election to the Maharashtra Assembly from Bandra East, where Congress heavyweight and former chief minister Narayan Rane is taking on Shiv Sena and MIM rivals. In Tasgaon-Kavthe Mahankal, where Suman Patil, wife of former home minister and NCP stalwart late R R Patil is contesting, around 58 per cent polling was reported, an election official said. Two sons of Rane were placed under preventive detention by police after the voting began this morning and were released after the polling ended. Nilesh Rane, a former Congress MP, and MLA Nitesh Rane, were detained at Kherwadi and Vakola police stations respectively. Rane, who lost the Assembly poll last year from his native Sindhudurg district in coastal Konkan, is trying to enter the Maharashtra Assembly through the bypoll to the Bandra (East) constituency in the metropolis.