jQuery Error – Uncaught TypeError: .find is not a function [closed]

I am having a modal with a Select Menu. I am getting the id assistant_id_1 of the select menu but i am trying to get the value assistant_name to hidden input assistant_name_1 so i can use it in php code $assistant_id_1_name = $_REQUEST["assistant_name_1"];

HTML code:
<div class="form-group row">
    <label for="assistant_id_1" class="col-xs-4 col-form-label">Assistant 1:</label>
    <div class="col-xs-5 form-group">
        <input type="hidden" name="assistant_name_1" id="assistant_name_1">
        <select id="assistant_id_1" name="assistant_id_1" class="form-control select2" style="width:100%;">
            <option value="">Please Select</option>
        </select>
    </div>
</div>

JS code:
$(document).ready(function() {
    get_assistant('#assistant_id_1');
    $('#recall_modal').modal('show');
});

function get_assistant(ele, selected = 0, filter = 'None') {
    var action = "assistant";
    $.ajax({
        type: "GET",
        url: 'api/get_data.php',
        dataType: 'json',
        data: {
            action: action,
            filter: filter
        },
        success: function(result) {
            if (result.success === true) {
                html = '<option value="">Please Select</option>';
                $.each(result.assistant, function(key, value) {
                    html += '<option value="' + value.assistant_id + '"';
                    if (value.assistant_id == selected) {
                        html += ' selected';
                    }
                    html += '>' + value.assistant_name + '</option>';
                });
                $(ele).html(html);
            }
        }
    });
}

$('#assistant_id_1').change(function () {
    $('#assistant_name_1').val(('#assistant_id_1').find('option:selected').text())
})

I am getting an error Uncaught TypeError: "#assistant_id_1".find is not a function