I accidentally added a widget area called sidebar 1

There should be a line like this in your functions.php of the theme:

“register_sidebar”…

 <?php
    // ... some code before
    // 
    register_sidebar(array(
        'name'          => __('unwanted widget', 'your-textdomain'),
        'description' => __('Your new widget desciption', 'your-textdomain'),
        'id'            => 'your-new-widget-name'
    ));

    // ...some code after
 ?>

Search for that line and change it. Basically, simply rename your unwanted Sidebar 1 to something different.

You have overwritten the default widget with a new one and created a name conflict. Change the name of your unwanted widget, that should fix it.