ALTER TABLE `tblleads` ADD `first_name` VARCHAR(191) NOT NULL AFTER `name`, ADD `last_name` VARCHAR(191) NULL AFTER `first_name`;

UPDATE `tblleads` SET
    `first_name` = REPLACE(IF(
        LOCATE(' ', `name`) > 0,
        SUBSTRING(`name`, 1, LOCATE(' ', `name`) - 1),
        IFNULL(`name`, '')
    ), ' ', ''),
    `last_name` = REPLACE(IF(
        LOCATE(' ', `name`) > 0,
        SUBSTRING(`name`, LOCATE(' ', `name`) + 1),
        NULL
    ), ' ', '');