Можно выбрать по атрибуту id=
. Например:
txt = '''<div class="input-group ref-container "><input id="sys_display.incident.assignment_group" name="sys_display.incident.assignment_group" aria-labelledby="label.incident.assignment_group" type="search" autocomplete="off" autocorrect="off" value="PeopleSoft Reporting ONLY" ac_columns="u_full_name" data-type="ac_reference_input" data-completer="AJAXTableCompleter" data-dependent="" data-dependent-value="" data-ref-qual="" data-ref="incident.assignment_group" data-ref-key="null" data-ref-dynamic="false" data-name="assignment_group" data-table="sys_user_group" class="form-control element_reference_input " style="; " spellcheck="false" onfocus="if (!this.ac) addLoadEvent(function() {var e = gel('sys_display.incident.assignment_group'); if (!e.ac) new AJAXTableCompleter(gel('sys_display.incident.assignment_group'), 'incident.assignment_group', '', ''); e.ac.onFocus();})" aria-required="true" role="combobox" aria-autocomplete="list" aria-owns="AC.incident.assignment_group"><span class="ref_dynamic_placeholder">A new record with this value will be created automatically</span><span class="input-group-btn"><button id="lookup.incident.assignment_group" name="lookup.incident.assignment_group" type="button" class="btn btn-default" title="Lookup using list" aria-haspopup="true" data-for="sys_display.incident.assignment_group" data-type="ac_reference_input" tabindex="-1" role="button" aria-label="Look up value for field: Assignment group" data-original-title="Lookup using list"><span class="icon icon-search" aria-hidden="true"></span></button></span></div>'''
soup = BeautifulSoup(txt, 'html.parser')
s = soup.select_one('#sys_display\.incident\.assignment_group')['value']
print(s)
Распечатывает:
PeopleSoft Reporting ONLY
То же самое с:
s = soup.find(id="sys_display.incident.assignment_group")['value']
print(s)