select column by position

Is there a way to select a column in a table by its position rather than
the field name? If I understand correctly column position in a table is
fixed. I've not been able to find anything in the archives or docs to
indicate that it's possible to select by position.

For example:

CREATE TABLE Accessions (
accession_id INT8 PRIMARY KEY DEFAULT nextval('accession_id_seq'),
accenumb VARCHAR(255) NOT NULL,
instcode_id INT4 NOT NULL CONSTRAINT Accessions_instcode_id_fk
REFERENCES Institutions(institution_id),
accename VARCHAR(255)
);

I would like to select accession_id by indicating column 1 somehow. Is
this at all possible?

Cheers,
Jennifer

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