* Cleco move follows Entergy into Midwest ISO * Move could be another loss to SPP power grid * Cleco hopes to integrate into MISO by Jan. 2014 By Scott DiSavino Dec 7 (Reuters) - Louisiana power company Cleco Corp on Friday said it filed a request with Louisiana utility regulators to join the group that operates much of the power grid in the U.S. Midwest. Cleco's decision to join the Midwest Independent Transmission System Operator (MISO), follows a move by its much bigger