Oracle 21c

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create table your_table (id number, description clob);
insert into your_table (id, description)
select 1, 'Just ASCII' from dual union all
select 2, 'With Chinese 好世界 text' from dual union all
select 3, 'With Russian Привет, мир text' from dual
3 rows affected

select * from your_table


ID
DESCRIPTION


1
Just ASCII

2
With Chinese 好世界 text

3
With Russian Привет, мир text


select *
from your_table
where regexp_instr(description, unistr('[\2E80-\2FD5\3190-\319f\3400-\4DBF\4E00-\9FCC\F900-\FAAD]')) > 0


ID
DESCRIPTION


2
With Chinese 好世界 text

ID	DESCRIPTION
1	Just ASCII
2	With Chinese 好世界 text
3	With Russian Привет, мир text