Solution 1:

NSIndexPath *selectedIndexPath = [tableView indexPathForSelectedRow];

Solution 2:

Get current selected row. May be helpful if you have only one section.

- (NSUInteger)currentSellectedRowIndex
{
    NSIndexPath *selectedIndexPath = [self.tableView indexPathForSelectedRow];
    if (selectedIndexPath) {
        return selectedIndexPath.row;
    }
    else {
        return NSNotFound;
    }
}