Oracle 18c

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create table your_table(id, name, address, doc) as
select 1, '{1:mark,2:john}', '{1:Home,2:Work,3:Club}', '{NI:299,Pass:A159}' from dual union all
select 2, '{1:Max,2:Mo}', '{1:Home}', '{NI:300011}' from dual
2 rows affected

select regexp_substr(name, '({|,)' || 2 || ':(.*?)(,|})', 1, 1, null, 2) as result
from your_table
where id = 1

RESULT

john

select regexp_substr(name, '({|,)' || 1 || ':(.*?)(,|})', 1, 1, null, 2) as result
from your_table
where id = 1

RESULT

mark

select regexp_substr(name, '({|,)' || 3 || ':(.*?)(,|})', 1, 1, null, 2) as result
from your_table
where id = 1

RESULT

null

select regexp_substr(address, '({|,)' || 3 || ':(.*?)(,|})', 1, 1, null, 2) as result
from your_table
where id = 1

RESULT

Club